04-Layer 3—IP Services Configuration Guide

HomeSupportSwitchesS6800 SeriesConfigure & DeployConfiguration GuidesH3C S6800 Switch Series Configuration Guide-Release 26xx-6W10704-Layer 3—IP Services Configuration Guide
10-UDP helper configuration
Title Size Download
10-UDP helper configuration 82.53 KB

Configuring UDP helper

Overview

UDP helper can provide the following packet conversion for packets with specific UDP destination port numbers:

·     Convert broadcast to unicast, and forward the unicast packets to specific destinations.

·     Convert broadcast to multicast, and forward the multicast packets.

Configuration restrictions and guidelines

When you configure UDP helper, follow these restrictions and guidelines:

·     By default, an interface on the device does not receive directed broadcasts destined for the directly connected network. To use UDP helper, execute the ip forward-broadcast command. For more information about receiving directed broadcasts destined for the directly connected network, see "Optimizing IP performance."

·     Do not set UDP ports 67 and 68 for UDP helper, because UDP helper cannot forward DHCP broadcast packets.

·     You can specify a maximum of 256 UDP ports for UDP helper.

·     You can specify a maximum of 20 unicast and multicast addresses for UDP helper to convert broadcast packets on an interface.

Configuring UDP helper to convert broadcast to unicast

You can configure UDP helper to convert broadcast packets with specific UDP port numbers to unicast packets.

Upon receiving a UDP broadcast packet, UDP helper uses the configured UDP ports to match the UDP destination port number of the packet.

·     If a match is found, UDP helper duplicates the packet and modifies the destination IP address of the copy to the configured unicast address. Then UDP helper forwards the unicast packet to the unicast address.

·     If no match is found, UDP helper does not process the packet.

To configure UDP helper to convert broadcast to unicast:

 

Step

Command

Remarks

1.     Enter system view.

system-view

N/A

2.     Enable UDP helper.

udp-helper enable

By default, UDP helper is disabled.

3.     Specify a UDP port number.

udp-helper port { port-number | dns | netbios-ds | netbios-ns | tacacs | tftp | time }

By default, no UDP port numbers are specified.

4.     Enter interface view.

interface interface-type interface-number

N/A

5.     Specify a destination server for UDP helper to convert broadcast to unicast.

udp-helper server ip-address [ global | vpn-instance vpn-instance-name ]

By default, no destination server is specified.

If you specify multiple destination servers, UDP helper creates one copy for each server.

Use this command on the interface that receives broadcast packets.

 

Configuring UDP helper to convert broadcast to multicast

You can configure UDP helper to convert broadcast packets with specific UDP port numbers to multicast packets.

Upon receiving a UDP broadcast packet, UDP helper uses the configured UDP ports to match the UDP destination port number of the packet.

·     If a match is found, UDP helper duplicates the packet and modifies the destination IP address of the copy to the configured multicast address. Then UDP helper forwards the packet to the multicast group.

·     If no match is found, UDP helper does not process the packet.

To configure UDP helper to convert broadcast to multicast:

 

Step

Command

Remarks

1.     Enter system view.

system-view

N/A

2.     Enable UDP helper.

udp-helper enable

By default, UDP helper is disabled.

3.     Specify a UDP port number.

udp-helper port { port-number | dns | netbios-ds | netbios-ns | tacacs | tftp | time }

By default, no UDP port numbers are specified.

4.     Enter interface view.

interface interface-type interface-number

N/A

5.     Specify a destination multicast address for UDP helper to convert broadcast to multicast.

udp-helper broadcast-map multicast-address [ acl acl-number ]

By default, no destination multicast address is specified for UDP helper.

If you specify multiple multicast addresses, UDP helper creates one copy for each address.

Use this command on the interface that receives broadcast packets.

 

Displaying and maintaining UDP helper

Execute display command in any view and reset commands in user view.

 

Task

Command

Display information about broadcast to unicast conversion by UDP helper on an interface.

display udp-helper interface interface-type interface-number

Clear packet statistics for UDP helper.

reset udp-helper statistics

 

UDP helper configuration examples

Configuring UDP helper to convert broadcast to unicast

Network requirements

As shown in Figure 1, configure UDP helper to convert broadcast to unicast on VLAN-interface 1 of Switch A. This feature enables Switch A to forward broadcast packets with UDP destination port number 55 to the destination server 10.2.1.1/16.

Figure 1 Network diagram

 

Configuration procedure

Make sure Switch A can reach the subnet 10.2.0.0/16.

# Enable UDP helper.

[SwitchA] System-view

[SwitchA] udp-helper enable

# Enable the UDP port 55 for UDP helper.

[SwitchA] udp-helper port 55

# Assign IP address 10.110.1.1/16 to VLAN-interface 1, and enable the interface to forward directed broadcast packets destined for the directly connected network.

[SwitchA] interface vlan-interface 1

[SwitchA-Vlan-interface1] ip address 10.110.1.1 16

[SwitchA-Vlan-interface1] ip forward-broadcast

# Specify destination server 10.2.1.1 for UDP helper to convert broadcast to unicast on VLAN-interface 1.

[SwitchA-Vlan-interface1] udp-helper server 10.2.1.1

Verifying the configuration

# Display information about broadcast to unicast conversion by UDP helper on VLAN-interface 1.

[SwitchA-Vlan-interface1] display udp-helper interface vlan-interface 1

Interface                Server VPN instance           Server address Packets sent

Vlan-interface1          N/A                           10.2.1.1       5

Configuring UDP helper to convert broadcast to multicast

Network requirements

As shown in Figure 2, VLAN-interface 1 of Switch B can receive multicast packets destined to 225.1.1.1.

Configure UDP helper to convert broadcast to multicast on VLAN-interface 1 of Switch A. This feature enables Switch A to forward broadcast packets with UDP destination port number 55 to the multicast group 225.1.1.1.

Figure 2 Network diagram

 

Configuration procedure

Make sure Switch A can reach the subnet 10.2.0.0/16.

1.     Configure Switch A:

# Enable UDP helper.

<SwitchA> system-view

[SwitchA] udp-helper enable

# Enable the UDP port 55 for UDP helper.

[SwitchA] udp-helper port 55

# Assign IP address 10.110.1.1/16 to VLAN-interface 1, and enable the interface to forward directed broadcast packets destined for the directly connected network.

[SwitchA] interface vlan-interface 1

[SwitchA-Vlan-interface1] ip address 10.110.1.1 16

[SwitchA-Vlan-interface1] ip forward-broadcast

# Configure UDP helper to convert broadcast packets to multicast packets destined for 225.1.1.1.

[SwitchA-Vlan-interface1] udp-helper broadcast-map 225.1.1.1

[SwitchA-Vlan-interface1] quit

# Enable IP multicast routing globally.

[SwitchA] multicast routing

[SwitchA-mrib] quit

Enable PIM-DM on VLAN-interface 1.

[SwitchA] interface vlan-interface 1

[SwitchA-Vlan-interface1] pim dm

[SwitchA-Vlan-interface1] quit

# Enable PIM-DM and IGMP on VLAN-interface 2.

[SwitchA] interface vlan-interface 2

[SwitchA-Vlan-interface2] pim dm

[SwitchA-Vlan-interface2] igmp enable

# Configure VLAN-interface 2 as a static member of multicast group 225.1.1.1.

[SwitchA-Vlan-interface2] igmp static-group 225.1.1.1

2.     Configure Switch B:

# Enable IP multicast routing globally.

<SwitchB> system-view

[SwitchB] multicast routing

[SwitchB-mrib] quit

# Enable PIM-DM and IGMP on VLAN-interface 1.

[SwitchB] interface vlan-interface 1

[SwitchB-Vlan-interface1] pim dm

[SwitchB-Vlan-interface1] igmp enable

# Configure VLAN-interface 1 as a static member of multicast group 225.1.1.1.

[SwitchB-Vlan-interface1] igmp static-group 225.1.1.1

Verifying the configuration

Verify that you can capture multicast packets from Switch A on Switch B.

  • Cloud & AI
  • InterConnect
  • Intelligent Computing
  • Security
  • SMB Products
  • Intelligent Terminal Products
  • Product Support Services
  • Technical Service Solutions
All Services
  • Resource Center
  • Policy
  • Online Help
All Support
  • Become a Partner
  • Partner Resources
  • Partner Business Management
All Partners
  • Profile
  • News & Events
  • Online Exhibition Center
  • Contact Us
All About Us
新华三官网