IGMP/Multicast with EIGRP

r_durant

[edit - do not double post;pw]

I've searched through the CCNP posts, and I see mostly references to switching when it comes to multicasting/igmp. I've never worked with this before, but today I was thrown into the shark pool head first. There's an application running over one of our WANs which is supposed to be using UDP and UDP multicasts. I'm hoping for some advice...

I have 4 sites, running over a Metro-Ethernet WAN. EIGRP configured on each router. The config is simple IMO. Having never worked with multicasting/igmp before, I decided to google....

The only 2 commands that I added based on what I found in order to enable multicast routing and IGMP, were 'ip multicast-routing' in exec mode and 'ip pim dense-mode' on each interface. Note that I am not sure I understand the difference between dense-mode and sparse-mode.

Here comes the issue, once IGMP is enabled on the WAN interface, the adjacencies of 2 sites drop after some time. The difference between these 2 sites, is that the routers are 'older' than the other 2. The 2 routers that drop the adjancies are 1841 running IOS 'c1841-ipbase-mz.124-15.T10.bin', the 2 that keep the adjacencies are 1941 running IOS 'c1900-universalk9-mz.SPA.151-4.M3.bin'.

Once I disable IGMP (no ip pim dense-mode) on the WAN interface the adjacencies on the 1841 routers come back up.

My question is, why would these particular adjacenies drop? I'm not sure how to start to troubleshoot, but I am sure it either has something to do with the IGMP config on those 2 'older' routers.

Here are the configs:

One of the 1941 routers:
hostname DCSECRTR
!
no aaa new-model
!
no ipv6 cef
ip source-route
ip cef
!
ip multicast-routing
!
ip domain name yourdomain.com
!
multilink bundle-name authenticated
!
redundancy
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
ip address 10.10.10.30 255.255.255.240
ip pim dense-mode
duplex auto
speed auto
!
interface GigabitEthernet0/1
ip address 192.168.0.164 255.255.255.224
ip pim dense-mode
duplex auto
speed auto
!
router eigrp 30
network 10.10.10.16 0.0.0.15
network 192.168.0.160 0.0.0.31
redistribute static
!

One of the 1841 routers:
hostname BSSECRTR
!
no aaa new-model
ip cef
!
ip multicast-routing
multilink bundle-name authenticated
!
archive
log config
hidekeys
!
interface FastEthernet0/0
description Interface to Security LAN
ip address 10.10.10.14 255.255.255.240
ip pim dense-mode
duplex auto
speed auto
!
interface FastEthernet0/1
description Interface to MetroE WAN
ip address 192.168.0.161 255.255.255.224
ip pim dense-mode
duplex auto
speed auto
!
router eigrp 30
network 10.10.10.0 0.0.0.15
network 192.168.0.160 0.0.0.31
no auto-summary
!

1841 Router:
hostname LGSECRTR
!
no aaa new-model
ip cef
!
ip multicast-routing
multilink bundle-name authenticated
!
archive
log config
hidekeys
!
interface FastEthernet0/0
ip address 10.10.10.46 255.255.255.240
ip pim dense-mode
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 192.168.0.163 255.255.255.224
ip pim dense-mode
duplex auto
speed auto
!
router eigrp 30
network 10.10.10.32 0.0.0.15
network 192.168.0.160 0.0.0.31
no auto-summary
!

1941 router:
hostname ISQSECRTR
!
boot-start-marker
boot-end-marker
!
!
logging buffered 51200 warnings
enable secret 5 $1$MZsC$pR1mPPToYA2YJBbtgxd4v1
!
no aaa new-model
!
clock timezone Bdos -4 0
!
no ipv6 cef
ip source-route
ip cef
!
ip multicast-routing
!
ip domain name yourdomain.com
!
multilink bundle-name authenticated
!
redundancy
!
interface Embedded-Service-Engine0/0
no ip address
shutdown
!
interface GigabitEthernet0/0
description Local SEC Intf
ip address 10.10.10.78 255.255.255.240
ip pim dense-mode
duplex auto
speed auto
!
interface GigabitEthernet0/1
description SEC WAN Intf
ip address 192.168.0.165 255.255.255.224
ip pim dense-mode
duplex auto
speed auto
!
!
router eigrp 30
network 10.10.10.64 0.0.0.15
network 192.168.0.160 0.0.0.31
!
ip forward-protocol nd
!

dead_p00l

I work with some multicast but don't use EIGRP. I did find this. Maybe it will help.

Troubleshooting PIM Dense Mode

r_durant

Thanks, will take a look...

networker050184

When you enable PIM you are not enabling IGMP on the interface. PIM creates the trees for the multicast traffic and IGMP is used by hosts to signal group joins/leaves.

The difference between dense and sparse is the way the trees are built. Dense uses the 'flood and prune' method and sparse roots trees at the RP.

Multicast isn't something a lot of people easily get their heads around unfortunately.

Now why this isn't working on these two particular routers, I don't know. How long exactly is it before the adjacency drops? If you figure out the time frame then you can correlate it to some sort of timer that is expiring etc. Anything in the logs? Opened a TAC case?

r_durant

Seems like the config maybe ok, I'm seeing late collisions on those two routers only, and the adjacencies drop immediately after. I'll troubleshoot with the Telco tomorrow. Those interfaces are set to auto/auto, so I'll have to see what their NICs are set to.