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Hall of Fame Super Blue

Multicast woes

Hi all

I have the following very basic setup

Router 1 - 2800_lab

interface GigabitEthernet0/1

ip address 10.5.1.1 255.255.255.0

ip pim dense-mode

duplex full

speed 100

end

Router 2 - 2600_rtr2

interface FastEthernet0/1

ip address 10.5.1.2 255.255.255.0

ip pim dense-mode

speed auto

full-duplex

no cdp enable

no mop enabled

end

Both routers have "ip multicast-routing" enabled.

Both routers connect to a 3560 switch on their gi0/0 and fa0/1 interfaces respectively.

The 3560 switch has IGMP snooping turned on.

I also have a solaris server connected to the same switch - 10.5.1.12.

I ran a network sniffer on the solaris server and i am still seeing EIGRP updates coming through to the server

10.5.1.1 -> 224.0.0.10 IP D=224.0.0.10 S=10.5.1.1 LEN=60, ID=0, TOS=0xc0, TTL=2

10.5.1.2 -> 224.0.0.10 IP D=224.0.0.10 S=10.5.1.2 LEN=60, ID=0, TOS=0xc0, TTL=2

10.5.1.1 -> 224.0.0.10 IP D=224.0.0.10 S=10.5.1.1 LEN=60, ID=0, TOS=0xc0, TTL=2

10.5.1.2 -> 224.0.0.10 IP D=224.0.0.10 S=10.5.1.2 LEN=60, ID=0, TOS=0xc0, TTL=2

1) Why am i still seeing EIGRP multicast packets on the solaris server ?

2) Why do the following outputs make no mention of EIGRP 224.0.0.10

2800_lab#sh ip mroute

IP Multicast Routing Table

Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

L - Local, P - Pruned, R - RP-bit set, F - Register flag,

T - SPT-bit set, J - Join SPT, M - MSDP created entry,

X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

U - URD, I - Received Source Specific Host Report,

Z - Multicast Tunnel, z - MDT-data group sender,

Y - Joined MDT-data group, y - Sending to MDT-data group

Outgoing interface flags: H - Hardware switched, A - Assert winner

Timers: Uptime/Expires

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.0.1.40), 2d21h/00:02:56, RP 0.0.0.0, flags: DCL

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

GigabitEthernet0/1, Forward/Dense, 2d21h/00:00:00

(*, 239.255.255.254), 2d21h/00:02:54, RP 0.0.0.0, flags: DC

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

GigabitEthernet0/1, Forward/Dense, 2d21h/00:00:00

2800_lab#

2600_rtr2#sh ip mroute

IP Multicast Routing Table

Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,

L - Local, P - Pruned, R - RP-bit set, F - Register flag,

T - SPT-bit set, J - Join SPT, M - MSDP created entry,

X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,

U - URD, I - Received Source Specific Host Report

Outgoing interface flags: H - Hardware switched

Timers: Uptime/Expires

Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.254), 2d21h/00:02:04, RP 0.0.0.0, flags: DC

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

FastEthernet0/1, Forward/Dense, 2d21h/00:00:00

(*, 224.0.1.40), 2d21h/00:02:59, RP 0.0.0.0, flags: DCL

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

FastEthernet0/1, Forward/Dense, 2d21h/00:00:00

2600_rtr2#

Switch output

======================================================================

lab_sw1#sh ip igmp snooping groups

Vlan Group Type Version Port List

-------------------------------------------------------------

50 224.0.1.40 igmp v2 Fa0/1, Fa0/15

50 239.255.255.254igmp v2 Fa0/1, Fa0/4, Fa0/15

lab_sw1#sh ip igmp snooping mrouter

Vlan ports

---- -----

50 Fa0/1(dynamic), Fa0/15(dynamic)

lab_sw1#

Any insights much appreciated

Jon

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Multicast woes

Hi Jon,

IGMP and CGMP does not work for reserved multicast addresses and as EIGRP used 224.0.0.10 which is one of the address from reserved multicast address range IGMP will not work it and will be flooded on ethernet segment.

Even if you try to add these addresses via a static ip igmp snooping entry it will report as message as illegal multicast address.

HTH

Ankur

2 REPLIES
Cisco Employee

Re: Multicast woes

Hi Jon,

IGMP and CGMP does not work for reserved multicast addresses and as EIGRP used 224.0.0.10 which is one of the address from reserved multicast address range IGMP will not work it and will be flooded on ethernet segment.

Even if you try to add these addresses via a static ip igmp snooping entry it will report as message as illegal multicast address.

HTH

Ankur

Hall of Fame Super Blue

Re: Multicast woes

Hi Ankur

Many thanks for the reply and it does tie up with what i am seeing in my lab.

Jon

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