The Cisco PE router must be configured to implement Internet Group Management Protocol (IGMP) or Multicast Listener Discovery (MLD) snooping for each Virtual Private LAN Services (VPLS) bridge domain.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-96805	CISC-RT-000710	SV-105943r1_rule		Low

Description
IGMP snooping provides a way to constrain multicast traffic at Layer 2. By monitoring the IGMP membership reports sent by hosts within the bridge domain, the snooping application can set up Layer 2 multicast forwarding tables to deliver traffic only to ports with at least one interested member within the VPLS bridge, thereby significantly reducing the volume of multicast traffic that would otherwise flood an entire VPLS bridge domain. The IGMP snooping operation applies to both access circuits and pseudowires within a VPLS bridge domain.

Description

IGMP snooping provides a way to constrain multicast traffic at Layer 2. By monitoring the IGMP membership reports sent by hosts within the bridge domain, the snooping application can set up Layer 2 multicast forwarding tables to deliver traffic only to ports with at least one interested member within the VPLS bridge, thereby significantly reducing the volume of multicast traffic that would otherwise flood an entire VPLS bridge domain. The IGMP snooping operation applies to both access circuits and pseudowires within a VPLS bridge domain.

STIG	Date
Cisco IOS XR Router RTR Security Technical Implementation Guide	2019-12-20

Details

Check Text ( C-95641r1_chk )
Review the router configuration to verify that IGMP or MLD snooping has been configured for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain. l2vpn bridge group L2GROUP bridge-domain L2_BRIDGE_COI1 interface GigabitEthernet0/0/0/2 igmp snooping profile default If the router is not configured to implement IGMP or MLD snooping for each VPLS bridge domain, this is a finding.

Check Text ( C-95641r1_chk )

Review the router configuration to verify that IGMP or MLD snooping has been configured for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain.

l2vpn
bridge group L2GROUP
bridge-domain L2_BRIDGE_COI1
interface GigabitEthernet0/0/0/2
igmp snooping profile default

If the router is not configured to implement IGMP or MLD snooping for each VPLS bridge domain, this is a finding.

Fix Text (F-102485r1_fix)
Configure IGMP or MLD snooping for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain. RP/0/0/CPU0:R3(config)#l2vpn RP/0/0/CPU0:R3(config-l2vpn)#bridge group L2GROUP RP/0/0/CPU0:R3(config-l2vpn-bg)# bridge-domain L2_BRIDGE_COI1 RP/0/0/CPU0:R3(config-l2vpn-bg-bd)#interface GigabitEthernet0/0/0/2 RP/0/0/CPU0:R3(config-l2vpn-bg-bd-ac)#igmp snooping profile default RP/0/0/CPU0:R3(config-l2vpn-bg-bd-ac)#end

Fix Text (F-102485r1_fix)

Configure IGMP or MLD snooping for IPv4 and IPv6 multicast traffic respectively for each VPLS bridge domain.

RP/0/0/CPU0:R3(config)#l2vpn
RP/0/0/CPU0:R3(config-l2vpn)#bridge group L2GROUP
RP/0/0/CPU0:R3(config-l2vpn-bg)# bridge-domain L2_BRIDGE_COI1
RP/0/0/CPU0:R3(config-l2vpn-bg-bd)#interface GigabitEthernet0/0/0/2
RP/0/0/CPU0:R3(config-l2vpn-bg-bd-ac)#igmp snooping profile default
RP/0/0/CPU0:R3(config-l2vpn-bg-bd-ac)#end