· When link failures occur on the M-LAG member devices, communications among Host-1A, Host-2A, and Host-3A and among Host-1B, Host-2B, and Host-3B are not affected.

Figure 1 Network diagram

Device	Interface	IP address	Remarks
Device A	Loopback0	3.3.3.3/32	Loopback interface address. Router ID
	XGE 3/0/4	32.1.1.1/24	Device C: XGE 3/0/4
	XGE 3/0/5	N/A	CE-1: XGE3/0/1 M-LAG member interface.
	XGE 3/0/15	N/A	Host-2A, Host-2B
	XGE 3/0/1	21.1.1.1/24	Device B: XGE 3/0/1 Keepalive interface.
	XGE 3/0/2	N/A	Device B: XGE 3/0/2 M-LAG peer-link interface.
	XGE 3/0/3	N/A	Device B: XGE 3/0/3 M-LAG peer-link interface.
	Vlan 101	101.1.1.1/24	Interface of the Layer 3 link connecting the two M-LAG member devices, which is used for forwarding east-west traffic or allowing north-south traffic to escape.
	Vlan-interface 1001	10.0.1.1/24 2000::10:0:1:1/112	VLAN interface the M-LAG interface of VPNA
	Vlan-interface 1002	10.1.1.1/24 2000::10:0:2:1/112	VLAN interface the single-homed interface of VPNA
	Vlan-interface 2001	20.0.1.1/24 2000::20:0:2:1/112	VLAN interface the M-LAG interface of VPNB
	Vlan-interface 2002	20.1.1.1/24 2000::20:0:2:1/112	VLAN interface the single-homed interface of VPNB
Device B	Loopback0	4.4.4.4/32	Loopback interface address. Router ID.
	XGE 3/0/4	33.1.1.1/24	Device C: XGE 3/0/5
	XGE 3/0/5	N/A	CE-1: XGE3/0/2 M-LAG member interface.
	XGE 3/0/1	21.1.1.2/24	Device A: XGE 3/0/1 Keepalive interface.
	XGE 3/0/2	N/A	Device A: XGE 3/0/2 M-LAG peer-link interface.
	XGE 3/0/3	N/A	Device A: XGE 3/0/3 M-LAG peer-link interface.
	Vlan 101	101.1.1.2/24	Interface of the Layer 3 link connecting the two M-LAG member devices, which is used for forwarding east-west traffic or allowing north-south traffic to escape.
	Vlan-interface 1001	10.0.1.1/24 2000::10:0:1:1/112	VLAN interface the M-LAG interface of VPNA
	Vlan-interface 2001	20.0.1.1/24 2000::20:0:1:1/112	VLAN interface the M-LAG interface of VPNB
Device C	Loopback0	5.5.5.5/32	Loopback interface address. Router ID.
	XGE 3/0/4	32.1.1.2/30	Device A: XGE3/0/4
	XGE 3/0/5	33.1.1.2/30	Device B XGE3/0/4
	XGE 3/0/1	N/A	Host-3A, Host-3B
	Vlan-interface 1001	10.3.1.1/24 2000::10:3:1:1/112	VLAN interface for VPNA.
	Vlan-interface 2001	20.3.1.1/24 2000::20:3:1:1/112	VLAN interface for VPNB.
CE-1	XGE 3/0/1	N/A	Device A: XGE 3/0/5
	XGE 3/0/2	N/A	Device B XGE 3/0/5
	XGE 3/0/15	N/A	L2-LSW (connecting Host-1A and Host-1B)

Applicable product matrix

In addition to running an applicable software version, you must also install the most recent patch, if any.

Device	Software version
S10500, S10500X, S7600, S7600-X, S7600E-X, S7500X, S7500E	R7625 and later
S12500G-AF (type T cards)	R7625 and later
S12500G-AF (type S cards)	R8054P04 and later
S10500X-G, S7500X-G	R7754P04 and later
S5590XP-HI-G, S6520X-EI-G, S6520XP-EI-G	R7754P04 and later

Analysis

· Device A and Device B form an M-LAG system.

· Device A and Device B are connected to uplink device Device C through equal-cost routes.

· Device A and Device B act as Layer 3 gateways for CE-side users. The gateway devices support dual-active and VRRP networking modes. This example uses the dual-active mode. For information about the VRRP mode, see the example for configuring an M-LAG + VRRP network (campus).

· The L3VPN network is configured with both IPv4 and IPv6 settings.

· Configure critical VLAN interfaces on the peer-link between Device A and Device B to implement Layer 3 connectivity. Then, packets sent from the local single-homed or M-LAG interface can be routed to the other M-LAG member device when the link between Device A or Device B and uplink device Device C fails.

Restrictions and guidelines

All devices in this example were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

Configuring IP addresses and unicast routing protocols

# On Host-1A, specify the gateway address as 10.0.1.1/2000::10:0:1:1. On Host-2A, specify the gateway address as 10.1.1.1/2000::10:1:1:1. On Host-3A, specify the gateway address as 10.3.1.1/2000::10:3:1:1.

# On Host-1B, specify the gateway address as 20.0.1.1/2000::20:0:1:1. On Host-2B, specify the gateway address 20.1.1.1/2000::20:1:1:1. On Host-3A, specify the gateway address as 20.3.1.1/2000::20:3:1:1.

# Configure OSPF on the IP core network to advertise routes for subnets attached to the interfaces (including Loopback interfaces) on each node. Make sure the switches have connectivity to each other.

Configuring the M-LAG member devices

Procedure summary

· Configuring M-LAG

· Configure IGP

· Configuring MPLS L3VPN

· Configuring the interconnect links between the M-LAG member devices and users

Configuring M-LAG

Device A	Device B	Description	Remarks
m-lag system-mac 2-2-2	m-lag system-mac 2-2-2	Set the MAC address of the M-LAG system.	You must assign the same M-LAG system MAC address to the member devices in an M-LAG system.
m-lag system-number 1	m-lag system-number 2	Set the M-LAG system number.	You must assign different M-LAG system numbers to the member devices in an M-LAG system.
m-lag system-priority 123	m-lag system-priority 123	Set the M-LAG system priority.	You must set the same M-LAG system priority on the member devices in an M-LAG system.
m-lag standalone enable	m-lag standalone enable	(Optional.) Enable standalone mode for the M-LAG devices.	To avoid that two member devices both act the primary device after the M-LAG system splits, you can enable standalone mode before the M-LAG system splits.
m-lag restore-delay 300	m-lag restore-delay 300	Configure the M-LAG latency.	Set the maximum amount of time for the secondary M-LAG member device to synchronize data (such as MAC address entries) with the primary M-LAG member device during M-LAG system setup.
m-lag keepalive ip destination 21.1.1.2 source 21.1.1.1	m-lag keepalive ip destination 21.1.1.1 source 21.1.1.2	Configure the source and destination IPv4 addresses of keepalive packets.	N/A
interface Ten-gigabitethernetE3/0/1	interface Ten-gigabitethernetE3/0/1	Enter the interface view for the keepalive link.	N/A
port link-mode route	port link-mode route	Configure the interface for the keepalive link to operate in route mode as a Layer 3 interface.	N/A
ip address 21.1.1.1 24	ip address 21.1.1.2 24	Configure the source IPv4 address of keepalive packets.	N/A
quit	quit	Return to system view.	N/A
m-lag mad exclude interface Ten-gigabitethernetE3/0/1	m-lag mad exclude interface Ten-gigabitethernetE3/0/1	Exclude the interface for the keepalive link from the shutdown action by M-LAG MAD.	N/A
interface bridge-aggregation 1	interface bridge-aggregation 1	Create an Ethernet aggregate interface.	The interface is used as the peer link interface.
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
quit	quit	Return to system view.	N/A
interface range Ten-gigabitethernetE 3/0/2 Ten-gigabitethernetE 3/0/3	interface range Ten-gigabitethernetE 3/0/2 Ten-gigabitethernetE 3/0/3	Enter physical interface range view.	N/A
port link-aggregation group 1	port link-aggregation group 1	Assign the physical interface for the peer link to the peer link aggregation group.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 1	interface bridge-aggregation 1	Enter Ethernet aggregate interface view.	N/A
port m-lag peer-link 1	port m-lag peer-link 1	Specify the aggregate interface (Bridge-Aggregation 1) as the peer link interface.	N/A
undo mac-address static source-check enable	undo mac-address static source-check enable	Disable the static source check feature on the interface to avoid cross peer-link forwarding failure for traffic.	N/A
quit	quit	Return to system view.	N/A
lldp global enable	lldp global enable	Enable LLDP globally.	N/A

Configure IGP

Device A	Device B	Description	Remarks
router id 3.3.3.3	router id 4.4.4.4	Configure a router ID.	N/A
ospf 1	ospf 1	Enable OSPF	N/A
mpls ldp sync	mpls ldp sync	Configure LDP-OSPF synchronization.	LDP establishes LSPs based on the IGP optimal routes. MPLS traffic forwarding might be interrupted if the actions of LDP and IGP are not synchronized. After LDP-IGP synchronization is enabled, IGP advertises the actual cost of a link only when LDP convergence on the link is completed. Before LDP convergence is completed, IGP advertises the maximum cost of the link. In this way, the link is visible on the IGP topology, but IGP does not select this link as the optimal route when other links are available. In this way, the device can avoid discarding MPLS packets when no LDP LSP is established on the optimal route.
import-route direct	import-route direct	Redistribute direct routes in the OSPF process.	N/A
area 0	area 0	Create OSPF area 0.	N/A
quit	quit	Return to OSPF view.	N/A
Interface loopback 0	Interface loopback 0	Configure interface Loopback 0.	N/A
ip address 3.3.3.3 32	ip address 4.4.4.4 32	Configure the Loopback interface address.	N/A
ospf 1 area 0	ospf 1 area 0	Enable OSPF on the Loopback interface.	N/A
quit	quit	Return to system view.	N/A
interface Ten-gigabitethernetE 3/0/4	interface Ten-gigabitethernetE 3/0/4	Enter Ethernet interface view.	N/A
port link-mode route	port link-mode route	Configure the interface to operate in Layer 3 mode.	N/A
ip address 32.1.1.1 24	ip address 33.1.1.1 24	Configure an IPv4 address for the interface.	N/A
ospf 1 area 0	ospf 1 area 0	Enable OSPF on an interface.	N/A
ospf network-type p2p	ospf network-type p2p	Set the OSPF network type of the interface to P2P.	N/A
quit	quit	Return to system view.	N/A
vlan 101	vlan 101	Create VLAN 101.	N/A
quit	quit	Return to system view.	N/A
interface vlan-interface 101	interface vlan-interface 101	Create VLAN-interface 101.	Interface of the Layer 3 link connecting the two M-LAG member devices, which is used for forwarding east-west traffic or allowing north-south traffic or Layer 3 remote mirroring traffic to escape.
ip address 101.1.1.1 255.255.255.0	ip address 101.1.1.2 255.255.255.0	Assign an IPv4 address to VLAN-interface 101.	N/A
ospf 1 area 0	ospf 1 area 0	Enable OSPF on the interface.	N/A
ospf network-type p2p	ospf network-type p2p	Set the OSPF network type of the interface to P2P.	N/A
quit	quit	Return to system view.	N/A
m-lag mad exclude interface loopback 0	m-lag mad exclude interface loopback 0	Exclude all interfaces used by MPLS from the shutdown action by M-LAG MAD.	N/A
m-lag mad exclude interface Vlan-interface 101	m-lag mad exclude interface Vlan-interface 101	Exclude the VLAN interface from the shutdown action by M-LAG MAD.	N/A

Configuring MPLS L3VPN

Device A	Device B	Description	Remarks
mpls lsr-id 3.3.3.3	mpls lsr-id 4.4.4.4	Configure an MPLS LSR ID.	N/A
mpls ldp	mpls ldp	Enable LDP.	N/A
session protection	session protection	Configure session protection.	If two LDP peers have both a direct link and an indirect link in between, you can configure this feature to protect their LDP session when the direct link fails.
quit	quit	Return to system view.	N/A
Interface Ten-gigabitethernet 3/0/4	Interface Ten-gigabitethernet 3/0/4	Configure the interface interconnecting devices.	N/A
mpls enable	mpls enable	Enable MPLS on the interconnect interface.	N/A
mpls ldp enable	mpls ldp enable	Enable MPLS LDP on the interconnect interface.	N/A
quit	quit	Return to system view.	N/A
interface vlan-interface 101	interface vlan-interface 101	Enter the view of the critical VLAN interface for the M-LAG member interfaces.	N/A
mpls enable	mpls enable	Enable MPLS on the interconnect interface.	N/A
mpls ldp enable	mpls ldp enable	Enable MPLS LDP on the interconnect interface.	N/A
quit	quit	Return to system view.	N/A
ip vpn VPNA	ip vpn VPNA	Configure VPNA	N/A
route-distinguisher 100:1	route-distinguisher 100:1	Configure the RD.	N/A
vpn-target 100:1	vpn-target 100:1	Configure RTs.	N/A
quit	quit	Return to system view.	N/A
ip vpn VPNB	ip vpn VPNB	Configure VPNB.	N/A
route-distinguisher 100:2	route-distinguisher 100:2	Configure the RD.	N/A
vpn-target 100:2	vpn-target 100:2	Configure RTs.	N/A
quit	quit	Return to system view.	N/A
vlan 1001 to 1002	vlan 1001	Configure user VLANs for VPNA.	N/A
vlan 2001 to 2002	vlan 2001	Configure user VLANs for VPNB.	N/A
interface vlan-interface 1001	interface vlan-interface 1001	Configure the user VLAN interface for VPNA.	N/A
ip binding vpn-instance VPNA	ip binding vpn-instance VPNA	Bind VPNA to the interface.	N/A
ip address 10.0.1.1 24	ip address 10.0.1.1 24	Assign an IP address to the interface.	N/A
ipv6 address 2000::10:0:1:1 112	ipv6 address 2000::10:0:1:1 112	Assign an IPv6 address to the interface.	N/A
mac-address 1-1-1	mac-address 1-1-1	Configure the MAC address of the dual-active gateway.	N/A
quit	quit	Return to system view.	N/A
interface vlan-interface 2001	interface vlan-interface 2001	Configure the user VLAN interface for VPNB.	N/A
ip binding vpn-instance VPNB	ip binding vpn-instance VPNB	Bind VPNB to the interface.	N/A
ip address 20.0.1.1 24	ip address 20.0.1.1 24	Assign an IP address to the interface.	N/A
ipv6 address 2000::20:0:1:1 112	ipv6 address 2000::20:0:1:1 112	Assign an IPv6 address to the interface.	N/A
mac-address 1-1-2	mac-address 1-1-2	Configure the MAC address of the dual-active gateway.	N/A
quit	quit	Return to system view.	N/A
interface vlan-interface 1002	N/A	Configure the single-homed user VLAN interface for VPNA.	N/A
ip binding vpn-instance VPNA	N/A	Bind VPNA to the interface.	N/A
ip address 10.1.1.1 24	N/A	Assign an IP address to the interface.	N/A
ipv6 address 2000::10:1:1:1 112	N/A	Assign an IPv6 address to the interface.	N/A
quit	N/A	Return to system view.	N/A
interface vlan-interface 2002	N/A	Configure the single-homed user VLAN interface for VPNB.	N/A
ip binding vpn-instance VPNB	N/A	Bind VPNB to the interface.	N/A
ip address 20.1.1.1 24	N/A	Assign an IP address to the interface.	N/A
ipv6 address 2000::20:1:1:1 112	N/A	Assign an IPv6 address to the interface.	N/A
quit	N/A	Return to system view.	N/A
bgp 200	bgp 200	Enter BGP view.	N/A
peer 4.4.4.4 as-number 200	peer 3.3.3.3 as-number 200	Configure BGP peers	BGP peer relationship between the two M-LAG member devices, which is used for forwarding east-west traffic or allowing north-south traffic to escape.
peer 4.4.4.4 connect-interface loopback 0	peer 3.3.3.3 connect-interface loopback 0	Configure the interface connected to the BGP peer.	N/A
peer 5.5.5.5 as-number 200	peer 5.5.5.5 as-number 200	Configure BGP peers	N/A
peer 5.5.5.5 connect-interface loopback 0	peer 5.5.5.5 connect-interface loopback 0	Configure the interface connected to the BGP peer.	N/A
address-family vpnv4	address-family vpnv4	Enter VPNv4 view.	N/A
peer 4.4.4.4 enable	peer 3.3.3.3 enable	Establish an IPv4 MP-IBGP peer relationship between PEs.	N/A
peer 5.5.5.5 enable	peer 5.5.5.5 enable	Establish an IPv4 MP-IBGP peer relationship between PEs.	N/A
quit	quit	Return to BGP view.	N/A
address-family vpnv6	address-family vpnv6	Enter VPNv6 view.	N/A
peer 4.4.4.4 enable	peer 3.3.3.3 enable	Establish an IPv6 MP-IBGP peer relationship between PEs.	N/A
peer 5.5.5.5 enable	peer 5.5.5.5 enable	Establish an IPv6 MP-IBGP peer relationship between PEs.	N/A
quit	quit	Return to BGP view.	N/A
ip vpn-instance VPNA	ip vpn-instance VPNA	Enter VPNA instance view.	N/A
address-family ipv4 unicast	address-family ipv4 unicast	Enter IPv4 unicast address family view.	N/A
import-route direct	import-route direct	Import direct routes.	N/A
quit	quit	Return to VPNA instance view.	N/A
address-family ipv6 unicast	address-family ipv6 unicast	Enter IPv6 unicast address family view.	N/A
import-route direct	import-route direct	Import direct routes.	N/A
quit	quit	Return to VPNA instance view.	N/A
quit	quit	Return to BGP view.	N/A
ip vpn-instance VPNB	ip vpn-instance VPNB	Enter VPNA instance view.	N/A
address-family ipv4 unicast	address-family ipv4 unicast	Enter IPv4 unicast address family view.	N/A
import-route direct	import-route direct	Import direct routes.	N/A
quit	quit	Return to VPNB instance view.	N/A
address-family ipv6 unicast	address-family ipv6 unicast	Enter IPv6 unicast address family view.	N/A
import-route direct	import-route direct	Import direct routes.	N/A
quit	quit	Return to VPNB instance view.	N/A
quit	quit	Return to BGP view.	N/A
quit	quit	Return to system view.	N/A

Configuring the interconnect links between the M-LAG member devices and users

Device A	Device B	Description	Remarks
interface bridge-aggregation 2	interface bridge-aggregation 2	Create the Ethernet aggregate interface connecting to CE-1.	N/A
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
port m-lag group 1	port m-lag group 1	Assign the aggregate interface to M-LAG group 1.	N/A
port lacp system-priority 100	port lacp system-priority 101	Set the LACP priority.	Ensure that when a brain split (simultaneous failure of keepalive link and peer link) occurs, only the member port with higher priority (the smaller the value, the higher the priority) is selected.
quit	quit	Return to system view.	N/A
interface Ten-gigabitethernet 3/0/5	interface Ten-gigabitethernet 3/0/5	Enter the view of the physical interface connecting the M-LAG system to CE-1.	N/A
port link-aggregation group 2	port link-aggregation group 2	Assign the interfaces to an M-LAG group.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 2	interface bridge-aggregation 2	Enter Ethernet aggregate interface view.	N/A
port link-type trunk	port link-type trunk	Configure the link type of the port as trunk.	N/A
port trunk permit vlan 1001 2001	port trunk permit vlan 1001 2001	Specify the VLANs permitted by the port.	N/A
quit	quit	Return to system view.	N/A
interface Ten-gigabitethernet 3/0/15	N/A	Configure the single-homed interface.	N/A
port link-type trunk	N/A	Configure the link type of the port as trunk.	N/A
port trunk permit vlan 1002 2002	N/A	Specify VLANs permitted by the port.	N/A
quit	N/A	Return to system view.	N/A

Configuring uplink device Device C

Procedure summary

· Configure IGP

· Configuring MPLS L3VPN

· Configuring the downlinks towards users

Configure IGP

Device C	Description	Remarks
router id 5.5.5.5	Configure a router ID.	N/A
ospf 1	Enable OSPF.	N/A
mpls ldp sync	Configure LDP-OSPF synchronization.	LDP establishes LSPs based on the optimal IGP routes. MPLS traffic forwarding interruption might occur because the actions of LDP and IGP are not synchronized. After LDP-IGP synchronization is enabled, IGP advertises the actual cost of a link only when LDP convergence on the link is completed. Before LDP convergence is completed, IGP advertises the maximum cost of the link. In this way, the link is visible on the IGP topology, but IGP does not select this link as the optimal route when other links are available. In this way, the device can avoid discarding MPLS packets when no LDP LSP is established on the optimal route.
import-route direct	Redistribute direct routes in the OSPF process.	N/A
area 0	Create OSPF area 0.	N/A
quit	Return to OSPF view.	N/A
quit	Return to system view.	N/A
interface Loopback 0	Configure the Loopback interface.	N/A
ip address 5.5.5.5 255,255,255,255	Assign an IPv4 address to the Loopback interface.	N/A
ospf 1 area 0.0.0.0	Enable OSPF on the Loopback interface.	N/A
quit	Return to system view.	N/A
interface Ten-gigabitethernetE 3/0/4	Enter Ethernet interface view.	N/A
port link-mode route	Configure the interconnect port to operate in Layer 3 mode.	N/A
ip address 32.1.1.1 24	Configure an IPv4 address for the interface.	N/A
ospf 1 area 0	Enable OSPF on an interface.	N/A
ospf network-type p2p	Set the OSPF network type of the interface to P2P.	N/A
quit	Return to system view.	N/A
interface Ten-gigabitethernetE 3/0/5	Enter Ethernet interface view.	N/A
port link-mode route	Configure the interconnect port to operate in Layer 3 mode.	N/A
ip address 33.1.1.1 24	Configure an IPv4 address for the interface.	N/A
ospf 1 area 0	Enable OSPF on an interface.	N/A
ospf network-type p2p	Set the OSPF network type of the interface to P2P.	N/A
quit	Return to system view.	N/A
lldp global enable	Enable LLDP globally	N/A

Configuring MPLS L3VPN

Device C	Description	Remarks
mpls lsr-id 5.5.5.5	Configure an MPLS LSR ID.	N/A
mpls ldp	Enable LDP.	N/A
session protection	Configure session protection.	If two LDP peers have both a direct link and an indirect link in between, you can configure this feature to protect their LDP session when the direct link fails.
quit	Return to system view.	N/A
Interface Ten-gigabitethernet 3/0/4	Configure the interface interconnecting devices.	N/A
mpls enable	Enable MPLS on the interconnect interface.	N/A
mpls ldp enable	Enable MPLS LDP on the interconnect interface.	N/A
quit	Return to system view.	N/A
Interface Ten-gigabitethernet 3/0/5	Configure the interface interconnecting devices.	N/A
mpls enable	Enable MPLS on the interconnect interface.	N/A
mpls ldp enable	Enable MPLS LDP on the interconnect interface.	N/A
quit	Return to system view.	N/A
ip vpn VPNA	Configure VPNA	N/A
route-distinguisher 100:1	Configure the RD.	N/A
vpn-target 100:1	Configure RTs.	N/A
quit	Return to system view.	N/A
ip vpn VPNB	Configure VPNB.	N/A
route-distinguisher 100:2	Configure the RD.	N/A
vpn-target 100:2	Configure RTs.	N/A
quit	Return to system view.	N/A
vlan 1001	Configure a user VLAN for VPNA.	N/A
vlan 2001	Configure a user VLAN for VPNB.	N/A
quit	Return to system view.	N/A
interface vlan-interface 1001	Configure the user VLAN interface for VPNA.	N/A
ip binding vpn-instance VPNA	Bind VPNA to the VLAN interface.	N/A
ip address 10.3.1.1 24	Assign an IP address to the interface.	N/A
ipv6 address 2000::10:3:1:1 112	Assign an IPv6 address to the interface.	N/A
quit	Return to system view.	N/A
interface vlan-interface 2001	Configure the user VLAN interface for VPNB.	N/A
ip binding vpn-instance VPNB	Bind VPNA to the VLAN interface.	N/A
ip address 20.3.1.1 24	Assign an IP address to the interface.	N/A
ipv6 address 2000::20:3:1:1 112	Assign an IPv6 address to the interface.	N/A
quit	Return to system view.	N/A
bgp 200	Enter BGP view.	N/A
peer 3.3.3.3 as-number 200	Configure BGP peers	N/A
peer 3.3.3.3 connect-interface loopback 0	Configure the interface connected to the BGP peer.	N/A
peer 4.4.4.4 as-number 200	Configure BGP peers	N/A
peer 4.4.4.4 connect-interface loopback 0	Configure the interface connected to the BGP peer.	N/A
address-family vpnv4	Enter VPNv4 view.	N/A
peer 3.3.3.3 enable	Establish an IPv4 MP-IBGP peer relationship between PEs.	N/A
peer 4.4.4.4 enable	Establish an IPv4 MP-IBGP peer relationship between PEs.	N/A
quit	Return to BGP view.	N/A
address-family vpnv6	Enter VPNv6 view.	N/A
peer 3.3.3.3 enable	Establish an IPv6 MP-IBGP peer relationship between PEs.	N/A
peer 4.4.4.4 enable	Establish an IPv6 MP-IBGP peer relationship between PEs.	N/A
quit	Return to BGP view.	N/A
ip vpn-instance VPNA	Enter VPNA view.	N/A
address-family ipv4 unicast	Enter IPv4 unicast address family view.	N/A
balance 2	Enable load balancing and set the maximum number of routes for load balancing.	N/A
import-route direct	Import direct routes.	N/A
quit	Return to VPNA instance view.	N/A
address-family ipv6 unicast	Enter IPv6 unicast address family view.	N/A
balance 2	Enable load balancing and set the maximum number of routes for load balancing.	N/A
import-route direct	Import direct routes.	N/A
quit	Return to VPNA instance view.	N/A
quit	Return to BGP view.	N/A
ip vpn-instance VPNB	Enter VPNB instance view.	N/A
address-family ipv4 unicast	Enter IPv4 unicast address family view.	N/A
balance 2	Enable load balancing and set the maximum number of routes for load balancing.	N/A
import-route direct	Import direct routes.	N/A
quit	Return to VPNB instance view.	N/A
address-family ipv6 unicast	Enter IPv6 unicast address family view.	N/A
balance 2	Enable load balancing and set the maximum number of routes for load balancing.	N/A
import-route direct	Import direct routes.	N/A
quit	Return to VPNB instance view.	N/A
quit	Return to BGP view.	N/A
quit	Return to system view.	N/A

Configuring the downlinks towards users

Device C	Description	Remarks
interface Ten-gigabitethernet 3/0/1	Enter the view of the Ethernet interface connected to the user	N/A
port link-type trunk	Configure the link type of the port as trunk.	N/A
port trunk permit vlan 1001 2001	Specify VLANs permitted by the port.	N/A
quit	Return to system view.	N/A

Configuring access device CE-1

Procedure summary

· Configuring the interconnect links between the CE and M-LAG system

· Configuring the interconnect link between the CE and endpoints

Configuring the interconnect links between the CE and M-LAG system

CE-1	Description	Remarks
vlan 1001	Create a service VLAN.	N/A
vlan 2001	Create a service VLAN.	N/A
quit	Return to system view.	N/A
interface bridge-aggregation 2	Create the Ethernet aggregate interface connecting to M-LAG.	N/A
link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
quit	Return to system view.	N/A
interface range Ten-gigabitethernet 3/0/1 to Ten-gigabitethernet 3/0/2	Enter the view of the physical interfaces connecting the CE to the M-LAG system.	N/A
port link-aggregation group 2	Add the interfaces to Ethernet aggregation group 2.	N/A
quit	Return to system view.	N/A
interface bridge-aggregation 2	Enter Ethernet aggregate interface view.	N/A
port link-type trunk	Configure the link type of the port as trunk.	N/A
port trunk permit vlan 1001 2001	Configure the aggregate interface to permit the specified VLANs.	N/A
quit	Return to system view.	N/A

Configuring the interconnect link between the CE and endpoints

CE-1	Description	Remarks
interface Ten-gigabitethernet 3/015	Enter the view of the Ethernet interface connected to the endpoints.	N/A
port link-type trunk	Configure the link type of the port as trunk.	N/A
port trunk permit vlan 1001 2001	Configure the aggregate interface to permit the specified VLANs.	N/A
quit	Return to system view.	N/A

Traffic forwarding models

About the traffic model

The traffic model contains the following information:

· ID—Traffic ID, in O-X-XXX format. The first segment (O) represents overlay traffic. The second segment (X) represents the IP version (4 for IPv4 and 6 for IPv6). The third segment (XXX) represents a unique number for the traffic.

· Type—Traffic type, such as known unicast/IPv4 and unicast/L2.

· Direction—Traffic direction, such as inter M-LAG east-west traffic and north-west traffic.

· Path—The nodes that the traffic traverses from the source to the destination.

· Simulation method—Traffic simulation method. Testers are used to simulate the patterns of traffic on the network set up in this example.

· Simulation traffic load—The network can be tested under light load (fewer than 1000 simulation traffic flows) or heavy load (more than 1000 simulation traffic flows).

Traffic

ID	Type	Direction	Path	Simulation method	Simulation traffic load	Traffic direction to FW/LB	Remarks
O-4-001	Known unicast/IPv4	Across MPLS	Host1-Device A/B-Device C-Host3	Tester	Light	N/A	Traffic is forwarded over the Layer 3 link between the M-LAG member devices when the uplink fails.
O-4-002	Known unicast/IPv4	Across MPLS	Host2-Device A-Device C-Host3	Tester	Light	N/A
O-6-001	Known unicast/IPv6	Across MPLS	Host1-Device A/B-Device C-Host3	Tester	Light	N/A
O-6-002	Known unicast/IPv6	Across MPLS	Host2-Device A-Device C-Host3	Tester	Light	N/A

Testing network convergence upon single points of failure

Failure test results

Table 1 Link failure test results

Device	Failure type	Traffic interruption time	Remarks
Device A	Single M-LAG member link failure	≤ 400 ms	N/A
	Recovery from a single M-LAG member link failure	≤ 100 ms	N/A
	Single uplink failure	≤ 400 ms	N/A
	Recovery from a single uplink failure	≤ 100 ms	N/A
	Complete peer link failure	≤ 400 ms	Focus on M-LAG interface services. Single-homed interface services are not assured.
	Recovery from a complete peer link failure	≤ 400 ms	Focus on M-LAG interface services. Single-homed interface services can be restored.
	Keepalive link failure	0 ms	N/A
	Recovery from keepalive link failure	0 ms	N/A
	Recovery from a keepalive link and peer link failure	≤ 30 s	Focus on M-LAG interface services. Single-homed interface services are not assured.
	Recovery from a keepalive link and peer link failure	≤ 2 s	Focus on M-LAG interface services. Single-homed interface services can be restored.
	Restart one M-LAG member device.	≤ 400 ms	Focus on M-LAG interface services. Single-homed interface services are not assured.
	Recovery from M-LAG member device restart	≤ 200 ms	Focus on M-LAG interface services. Single-homed interface services can be restored.
	Switching fabric module failure	≤ 100 ms	N/A
	Recovery from a switching fabric module failure	≤ 100 ms	N/A

Verifying the configuration

Commands

Table 2 Verification commands

Device A	Device B	Description
display m-lag summary	display m-lag summary	Displays summary information about the IPP and DR interfaces in the DR system.
display m-lag keepalive	display m-lag keepalive	Displays DR keepalive packet statistics.
display m-lag role	display m-lag role	Displays DR role information.
display m-lag verbose	display m-lag verbose	Displays detailed information about the peer-link interface and M-LAG interfaces.
display mpls ldp lsp	display mpls ldp lsp	Displays LDP LSP information.
display ip routing-table vpn-instance	display ip routing-table vpn-instance	Displays IPv4 routing information of a VPN instance.
display ipv6 routing-table vpn-instance	display ipv6 routing-table vpn-instance	Displays IPv6 routing information of a VPN instance.

Procedure

Verifying that the M-LAG system is operating correctly

Verify that the M-LAG system is set up correctly on Device A and Device B.

# Display summary information about the peer-link interface and M-LAG interfaces.

<Device A>display m-lag summary

Flags: A -- Aggregate interface down, B -- No peer M-LAG interface configured

C -- Configuration consistency check failed

Peer-link interface: BAGG1

Peer-link interface state (cause): UP

Keepalive link state (cause): UP

M-LAG interface information

M-LAG IF M-LAG group Local state (cause) Peer state Remaining down time(s)

BAGG2 1 UP UP -

<Device B>display m-lag summary

Flags: A -- Aggregate interface down, B -- No peer M-LAG interface configured

C -- Configuration consistency check failed

Peer-link interface: BAGG1

Peer-link interface state (cause): UP

Keepalive link state (cause): UP

M-LAG interface information

M-LAG IF M-LAG group Local state (cause) Peer state Remaining down time(s)

BAGG2 1 UP UP -

# Display M-LAG keepalive packet statistics and verify that the keepalive packet receive and send status is successful.

[Device A]display m-lag keepalive

Neighbor keepalive link status (cause): Up

Neighbor is alive for: 635 s 341 ms

Keepalive packet transmission status:

Sent: Successful

Received: Successful

Last received keepalive packet information:

Source IP address: 21.1.1.2

Time: 2022/08/04 09:54:33

Action: Accept

M-LAG keepalive parameters:

Destination IP address: 21.1.1.2

Source IP address: 21.1.1.1

Keepalive UDP port : 6400

Keepalive VPN name : N/A

Keepalive interval : 1000 ms

Keepalive timeout : 5 sec

Keepalive hold time: 3 sec

[Device A]

[Device B]display m-lag keepalive

Neighbor keepalive link status (cause): Up

Neighbor is alive for: 650 s 860 ms

Keepalive packet transmission status:

Sent: Successful

Received: Successful

Last received keepalive packet information:

Source IP address: 21.1.1.1

Time: 2022/08/04 09:59:42

Action: Accept

M-LAG keepalive parameters:

Destination IP address: 21.1.1.1

Source IP address: 21.1.1.2

Keepalive UDP port : 6400

Keepalive VPN name : N/A

Keepalive interval : 1000 ms

Keepalive timeout : 5 sec

Keepalive hold time: 3 sec

[Device B]

# Display M-LAG role information.

[Device A]display m-lag role

Effective role information

Factors Local Peer

Effective role Secondary Primary

Initial role Secondary Primary

MAD DOWN state Yes No

Health level 0 0

Role priority 32768 32768

Bridge MAC 0cda-41c5-aab0 0000-fc00-8d3c

Effective role trigger: Peer link calculation

Effective role reason: MAD status

Configured role information

Factors Local Peer

Configured role Secondary Primary

Role priority 32768 32768

Bridge MAC 0cda-41c5-aab0 0000-fc00-8d3c

[Device A]

[Device B]disp m-lag role

Effective role information

Factors Local Peer

Effective role Primary Secondary

Initial role Primary Secondary

MAD DOWN state No Yes

Health level 0 0

Role priority 32768 32768

Bridge MAC 0000-fc00-8d3c 0cda-41c5-aab0

Effective role trigger: Peer link calculation

Effective role reason: MAD status

Configured role information

Factors Local Peer

Configured role Primary Secondary

Role priority 32768 32768

Bridge MAC 0000-fc00-8d3c 0cda-41c5-aab0

[Device B]

# Display detailed information about the peer-link interface and M-LAG interfaces.

<Device A>display m-lag verbose

Flags: A -- Home_Gateway, B -- Neighbor_Gateway, C -- Other_Gateway,

D -- PeerLink_Activity, E -- DRCP_Timeout, F -- Gateway_Sync,

G -- Port_Sync, H -- Expired

Peer-link interface/Peer-link interface ID: BAGG1/1

State: UP

Cause: N/A

Local DRCP flags/Peer DRCP flags: ABDFG/ABDFG

Local Selected ports (index): XGE3/0/2 (292), XGE3/0/3 (293)

Peer Selected ports indexes: 292, 293

M-LAG interface/M-LAG group ID: BAGG2/1

Local M-LAG interface state: UP

Peer M-LAG interface state: UP

M-LAG group state: UP

Local M-LAG interface down cause: N/A

Remaining M-LAG DOWN time: N/A

Local M-LAG interface LACP MAC: Config=N/A, Effective=0002-0002-0002

Peer M-LAG interface LACP MAC: Config=N/A, Effective=0002-0002-0002

Local M-LAG interface LACP priority: Config=32768, Effective=123

Peer M-LAG interface LACP priority: Config=32768, Effective=123

Local DRCP flags/Peer DRCP flags: ABDFG/ABDFG

Local Selected ports (index): XGE3/0/5 (295)

Peer Selected ports indexes: 291

<Device B>disp m-lag verbose

Flags: A -- Home_Gateway, B -- Neighbor_Gateway, C -- Other_Gateway,

D -- PeerLink_Activity, E -- DRCP_Timeout, F -- Gateway_Sync,

G -- Port_Sync, H -- Expired

Peer-link interface/Peer-link interface ID: BAGG1/1

State: UP

Cause: N/A

Local DRCP flags/Peer DRCP flags: ABDFG/ABDFG

Local Selected ports (index): XGE3/0/2 (292), XGE3/0/3 (293)

Peer Selected ports indexes: 292, 293

M-LAG interface/M-LAG group ID: BAGG2/1

Local M-LAG interface state: UP

Peer M-LAG interface state: UP

M-LAG group state: UP

Local M-LAG interface down cause: -

Remaining M-LAG DOWN time: -

Local M-LAG interface LACP MAC: Config=N/A, Effective=0002-0002-0002

Peer M-LAG interface LACP MAC: Config=N/A, Effective=0002-0002-0002

Local M-LAG interface LACP priority: Config=32768, Effective=123

Peer M-LAG interface LACP priority: Config=32768, Effective=123

Local DRCP flags/Peer DRCP flags: ABDFG/ABDFG

Local Selected ports (index): XGE3/0/5 (295)

Peer Selected ports indexes: 291

Verifying LDP LSP information

# Display LDP peer and LDP session information on Device A.

[Device A]display mpls ldp peer

Total number of peers: 2

Peer LDP ID State Role GR MD5 KA Sent/Rcvd

5.5.5.5:0 Operational Passive Off Off 53/53

4.4.4.4:0 Operational Passive Off Off 48/48

[Device A]

# Display information about LSPs generated by LDP on Device A.

[Device A]display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup, N/A - unavailable

FECs: 3 Ingress: 2 Transit: 2 Egress: 1

FEC In/Out Label Nexthop OutInterface/LSINDEX

3.3.3.3/32 3/-

-/1151(L)

4.4.4.4/32 -/3 101.1.1.2 Vlan101

1150/3 101.1.1.2 Vlan101

-/1150(L)

5.5.5.5/32 -/1150(L)

-/3 32.1.1.2 XGE3/0/4

1151/3 32.1.1.2 XGE3/0/4

[Device A]

# Display LDP peer and LDP session information on Device B.

[Device B]display mpls ldp peer

Total number of peers: 2

Peer LDP ID State Role GR MD5 KA Sent/Rcvd

3.3.3.3:0 Operational Active Off Off 51/51

5.5.5.5:0 Operational Passive Off Off 51/51

[Device B]

# Display information about LSPs generated by LDP on Device B.

[Device B]display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup, N/A - unavailable

FECs: 3 Ingress: 2 Transit: 2 Egress: 1

FEC In/Out Label Nexthop OutInterface/LSINDEX

3.3.3.3/32 -/3 101.1.1.1 Vlan101

1151/3 101.1.1.1 Vlan101

-/1151(L)

4.4.4.4/32 3/-

-/1150(L)

5.5.5.5/32 -/1151(L)

-/3 33.1.1.2 XGE3/0/4

1150/3 33.1.1.2 XGE3/0/4

[Device B]

# Display LDP peer and LDP session information on Device C.

[Device C]display mpls ldp peer

Total number of peers: 2

Peer LDP ID State Role GR MD5 KA Sent/Rcvd

3.3.3.3:0 Operational Active Off Off 58/58

4.4.4.4:0 Operational Active Off Off 53/53

[Device C]

# Display information about LSPs generated by LDP on Device C.

[Device C]display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup

FECs: 3 Ingress: 2 Transit: 2 Egress: 1

FEC In/Out Label Nexthop OutInterface

3.3.3.3/32 -/3 32.1.1.1 XGE3/0/4

1151/3 32.1.1.1 XGE3/0/4

-/1151(L)

4.4.4.4/32 -/1150(L)

-/3 33.1.1.1 XGE3/0/5

1150/3 33.1.1.1 XGE3/0/5

5.5.5.5/32 3/-

-/1151(L)

-/1150(L)

[Device C]display mpls ldp peer

Total number of peers: 2

Peer LDP ID State Role GR MD5 KA Sent/Rcvd

3.3.3.3:0 Operational Active Off Off 58/58

4.4.4.4:0 Operational Active Off Off 53/53

[Device C]

[Device C]display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup

FECs: 3 Ingress: 2 Transit: 2 Egress: 1

FEC In/Out Label Nexthop OutInterface

3.3.3.3/32 -/3 32.1.1.1 XGE3/0/4

1151/3 32.1.1.1 XGE3/0/4

-/1151(L)

4.4.4.4/32 -/1150(L)

-/3 33.1.1.1 XGE3/0/5

1150/3 33.1.1.1 XGE3/0/5

5.5.5.5/32 3/-

-/1151(L)

-/1150(L)

Verifying IPv4 routing information of VPN instances

# Display IPv4 routing information of the VPN instances on Device A.

[Device A]display ip routing-table vpn-instance VPNA protocol bgp

Summary count : 1

BGP Routing table status : <Active>

Summary count : 1

Destination/Mask Proto Pre Cost NextHop Interface

10.3.1.0/24 BGP 255 0 5.5.5.5 XGE3/0/4

BGP Routing table status : <Inactive>

Summary count : 0

[Device A]

[Device A]display ip routing-table vpn-instance VPNB protocol bgp

Summary count : 1

BGP Routing table status : <Active>

Summary count : 1

Destination/Mask Proto Pre Cost NextHop Interface

20.3.1.0/24 BGP 255 0 5.5.5.5 XGE3/0/4

BGP Routing table status : <Inactive>

Summary count : 0

[Device A]

# Display IPv4 routing information of the VPN instances on Device B.

[Device B]display ip routing-table vpn-instance VPNA protocol bgp

Summary count : 2

BGP Routing table status : <Active>

Summary count : 2

Destination/Mask Proto Pre Cost NextHop Interface

10.1.1.0/24 BGP 255 0 3.3.3.3 Vlan101

10.3.1.0/24 BGP 255 0 5.5.5.5 XGE2/0/9

BGP Routing table status : <Inactive>

Summary count : 0

[Device B]display ip routing-table vpn-instance VPNB protocol bgp

Summary count : 2

BGP Routing table status : <Active>

Summary count : 2

Destination/Mask Proto Pre Cost NextHop Interface

20.1.1.0/24 BGP 255 0 3.3.3.3 Vlan101

20.3.1.0/24 BGP 255 0 5.5.5.5 XGE2/0/9

BGP Routing table status : <Inactive>

Summary count : 0

[Device B]

# Display IPv4 routing information of the VPN instances on Device C.

[Device C]display ip routing-table vpn-instance VPNA protocol bgp

Summary count : 3

BGP Routing table status : <Active>

Summary count : 3

Destination/Mask Proto Pre Cost NextHop Interface

10.0.1.0/24 BGP 255 0 3.3.3.3 XGE1/0/2

4.4.4.4 XGE1/0/3

10.1.1.0/24 BGP 255 0 3.3.3.3 XGE1/0/2

BGP Routing table status : <Inactive>

Summary count : 0

[Device C]display ip routing-table vpn-instance VPNB protocol bgp

Summary count : 3

BGP Routing table status : <Active>

Summary count : 3

Destination/Mask Proto Pre Cost NextHop Interface

20.0.1.0/24 BGP 255 0 3.3.3.3 XGE1/0/2

4.4.4.4 XGE1/0/3

20.1.1.0/24 BGP 255 0 3.3.3.3 XGE1/0/2

BGP Routing table status : <Inactive>

Summary count : 0

[Device C]

Verifying IPv6 routing information of VPN instances

# Display IPv6 routing information of the VPN instances on Device A.

[Device A]display ipv6 routing-table vpn-instance VPNA protocol bgp

Summary count : 1

BGP4+ Routing table status : <Active>

Summary count : 1

Destination: 2000::10:3:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:5.5.5.5 Preference: 255

Interface : XGE3/0/4 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device A]

[Device A]display ipv6 routing-table vpn-instance VPNB protocol bgp

Summary count : 1

BGP4+ Routing table status : <Active>

Summary count : 1

Destination: 2000::20:3:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:5.5.5.5 Preference: 255

Interface : XGE3/0/4 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device A]

# Display IPv6 routing information of the VPN instances on Device B.

[Device B]display ipv6 routing-table vpn-instance VPNA protocol bgp

Summary count : 2

BGP4+ Routing table status : <Active>

Summary count : 2

Destination: 2000::10:1:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : Vlan101 Cost : 0

Destination: 2000::10:3:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:5.5.5.5 Preference: 255

Interface : XGE2/0/9 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device B]display ipv6 routing-table vpn-instance VPNB protocol bgp

Summary count : 2

BGP4+ Routing table status : <Active>

Summary count : 2

Destination: 2000::20:1:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : Vlan101 Cost : 0

Destination: 2000::20:3:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:5.5.5.5 Preference: 255

Interface : XGE2/0/9 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device B]

# Display IPv6 routing information of the VPN instances on Device C.

[Device C]display ipv6 routing-table vpn-instance VPNA protocol bgp

Summary count : 3

BGP4+ Routing table status : <Active>

Summary count : 3

Destination: 2000::10:0:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : XGE1/0/2 Cost : 0

Destination: 2000::10:0:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:4.4.4.4 Preference: 255

Interface : XGE1/0/3 Cost : 0

Destination: 2000::10:1:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : XGE1/0/2 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device C]display ipv6 routing-table vpn-instance VPNB protocol bgp

Summary count : 3

BGP4+ Routing table status : <Active>

Summary count : 3

Destination: 2000::20:0:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : XGE1/0/2 Cost : 0

Destination: 2000::20:0:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:4.4.4.4 Preference: 255

Interface : XGE1/0/3 Cost : 0

Destination: 2000::20:1:1:0/112 Protocol : BGP4+

NextHop : ::FFFF:3.3.3.3 Preference: 255

Interface : XGE1/0/2 Cost : 0

BGP4+ Routing table status : <Inactive>

Summary count : 0

[Device C]

Verifying host communication

Host 1A/Host2A and Host 3A can communicate with each other at dual stacks, and the same with Host 1B/Host 2B and Host 3B.

Verifying host communication in case of Device A or Device B downlink M-LAG member interface failure

Host 1A/Host 2A and Host 3A can still communicate with each other, and the same with Host 1B/Host 2B and Host 3B.

Verifying host communication in case of Device A or Device B uplink interface failure

Disconnect Device A from Device C. Verify that Host 1A/Host 2A and Host 3A can still communicate with each other, and the same with Host 1B/Host 2B and Host 3B. (After Device A is disconnected from Device C, traffic accessing Device A is switched to Device B for forwarding through the interconnect links between the two devices. Transient packet loss occurs during the traffic switchover process.)

Disconnect Device B from Device C. Verify that Host 1A/Host 2A and Host 3A can still communicate with each other, and the same with Host 1B/Host 2B and Host 3B. (After Device B is disconnected from Device C, traffic accessing Device B is switched to Device A for forwarding through the interconnect links between the two devices. Transient packet loss occurs during the traffic switchover process.)

Upgrade procedure

Pre-upgrade verification commands

Before you perform an upgrade, use the commands in Verifying the configuration and the commands in the following table to verify that all requirements are met for an upgrade.

Table 3 Pre-upgrade verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Upgrade procedure

Before you upgrade the device software, perform the following tasks:

1. Execute the display version command to verify the current BootWare image version and startup software version.

2. Use the release notes for the upgrade software version to evaluate the upgrade impact on your network and verify the following items:

¡ Software and hardware compatibility.

¡ Version and size of the upgrade software.

¡ Compatibility of the upgrade software with the current BootWare image and startup software image.

3. Use the release notes to verify whether the upgrade software images require a license. If licenses are required, check the system for availability of valid licenses. If no license exists on the device, first install a license. If you do not install a license, the software package will fail to be installed.

4. Use the dir command to verify that the device has sufficient storage space for the upgrade images. If the storage space is not sufficient, delete unused files by using the delete command. Make sure that all MPUs in the system have sufficient storage space.

5. After Device A and Device B form an M-LAG system, perform the following tasks:

a. Check the LLDP neighbors of Device A to obtain the LLDP state information of all interfaces on Device A.

b. Manually shut down all interfaces connecting to the other devices (except the peer-link and keepalive interfaces) on Device A to

c. Switch all incoming and outgoing traffic of Device A to Device B.

6. Save the configuration on Device A, and use FTP or TFTP to transfer the upgrade image file to the root directory of a file system. Upgrade Device A and reboot it.

7. When Device A is being rebooted, manually shut down the interconnect interfaces connecting Device B to Device A, typically the peer-link and keepalive interfaces.

8. After Device A is rebooted, bring up the interfaces that have been shut down on Device B. Wait for M-LAG to restore between Device A and Device B.

9. After Device A and Device B form a new M-LAG system again, bring up the interfaces connecting to the other devices. Wait for the traffic to restore.

For the detailed upgrade guide, see H3C Switches M-LAG System Upgrade Guide.

Upgrade the software. For more information about the software upgrade procedure, see the fundamentals configuration guide for the device.

Estimating upgrade downtime

See “Testing network convergence upon single points of failure.” The upgrade downtime of each device contains the traffic downtime for restart of one M-LAG member device and recovery from M-LAG member device restart.

Verifying the upgrade result

Execute the commands in "Verifying the configuration" and the following commands to verify that the device is upgraded successfully.

Table 4 Post-upgrade verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Expanding the network

Pre-expansion verification commands

Execute the commands in “Verifying the configuration" and the following commands to verify that the device is available for an expansion.

Table 5 Pre-expansion verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Expanding the network

1. Make sure the expansion device is not connected to the management network.

2. Upgrade the device to the target software version.

3. Configure the device.

4. Connect the device to the management network.

Estimating expansion downtime

N/A

Verifying the expansion result

After the expansion finishes, use the commands in the following table to verify that the expansion has been done correctly.

Table 6 Post-expansion verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacing hardware

Replacing a service module

Pre-replacement verification commands

Execute the commands in “Verifying the configuration" and the following commands to verify that the target device is available for a replacement.

Table 7 Command check summary before replacement

Device A	Device B	Description
display device	display device	Displays device information.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacing hardware

Before you replace an interface module, make sure the service and management traffic has switched over to other interface modules that are operating correctly.

Replace the interface modules online while the system is operating or power off the system before you do the replacement, depending on the evaluation of the conditions.

Verifying the traffic interruption time

See “Testing network convergence upon single points of failure.” The replacement downtime of each interface module contains the traffic downtime for single member link failure in an M-LAG interface, single uplink failure, recovery from a single member link failure in an M-LAG interface, and recovery from a single uplink failure.

Verifying the replacement result

Use the same commands for pre-replacement verification to verify that the system can operate correctly after the hardware replacement.

Replacing a switching fabric module

Pre-replacement verification commands

Execute the commands in "Verifying the configuration" and the following commands to verify that the target device is available for a replacement.

Table 8 Command check summary before replacement

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacing hardware

Power off the device and replace the switching fabric module, or replace the switching fabric module when the device is running. For more information, see the installation guides for the switching fabric module.

Verifying the traffic interruption time

See “Testing network convergence upon single points of failure.” The replacement downtime of each switching fabric module contains the traffic downtime for switching fabric module failure and recovery from a switching fabric module failure.

Verifying the replacement result

Use the same commands for pre-replacement verification to verify that the system can operate correctly after the hardware replacement.

H3C Campus Switches M-LAG Configuration Guide-6W101

Analysis

Configuring MPLS L3VPN

Configuring the interconnect link between the CE and endpoints

Testing network convergence upon single points of failure

Failure test results

Verifying the configuration

Verifying that the M-LAG system is operating correctly

Verifying LDP LSP information

Verifying IPv4 routing information of VPN instances

Verifying IPv6 routing information of VPN instances

Verifying host communication

Verifying host communication in case of Device A or Device B downlink M-LAG member interface failure

Verifying host communication in case of Device A or Device B uplink interface failure

Pre-replacement verification commands

Replacing hardware

Verifying the traffic interruption time

Verifying the replacement result

Pre-replacement verification commands

Replacing hardware

Verifying the traffic interruption time

Verifying the replacement result

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