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Cisco 4948 multicast config

SUNIL Perumana
Level 1
Level 1

Dear Support,

I have a Cisco 4948.I want to add static host to a multicast group.what is the config ? Please let me know.

Regards,

Sunil

1 Accepted Solution

Accepted Solutions

Hello Sunil,

>> But if I enter the Mac address it shows not a valid multicast Mac address

what MAC address are you entering?

Ganesh: ip igmp join-group is dangerous in production networks because it causes packets belonging to the multicast group to be process switched and sent to main cpu. It is very handy for doing tests in a lab environment.

Hope to help

Giuseppe

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9 Replies 9

Leo Laohoo
Hall of Fame
Hall of Fame

You're not trying to configure Multicast over VRF (mVRF) are you?

Ganesh Hariharan
VIP Alumni
VIP Alumni

Dear Support,

I have a Cisco 4948.I want to add static host to a multicast group.what is the config ? Please let me know.

Regards,

Sunil

Sunil,

ip igmp join-group --To configure an interface on the router to join the specified group or channel, use the ip igmp join-group command in interface configuration mode.

Hope to Help !!

Ganesh.H

Remember to rate the helpful post

Hi Ganesh,

The command  used with Cisco 3650

ip igmp snooping vlan 2  static mac multicast ip address int gi 1/1

The command used in Cisco 4948  is ip igmp snooping vlan 2  static mac address of the  group int gi 1/1

But if I enter the Mac address it shows not a valid multicast Mac address

Please assist me on this issue.

Regards,

Sunil

Hello Sunil,

>> But if I enter the Mac address it shows not a valid multicast Mac address

what MAC address are you entering?

Ganesh: ip igmp join-group is dangerous in production networks because it causes packets belonging to the multicast group to be process switched and sent to main cpu. It is very handy for doing tests in a lab environment.

Hope to help

Giuseppe

Hi Giuslar,

I am entering the mac address of the device containing multicast ip address.The scenario is there are 14 devices which contain multicast ip addresses which is terminated to my Cisco 4948 switch and i want the traffic to be divided into different ports i.e say 7 devices should be pass the traffic through first 7 ports and the other 7 should pass through the next 7 ports.

Regards,

Sunil P

Hello Sunil,

>> I am entering the mac address of the device containing multicast ip address.

I think the command you are trying to use expect to associate statically a multicast MAC address to a set of switch ports

a multicast address representing an IPv4 multicast address has a specific format:

OUI : The IANA owns the OUI MAC address 01:00:5e

so you need to take the less meaningful 23 bits of the 32 IPv4 multicast address

for example 239.0.10.20 is associated to

-> MAC 01:00:5e:00:0a:14

so you need to calculate the associated MAC addresses to each group and then you could set static settings

Edit:

example on a C4500

ip igmp snooping vlan 650 static 0100.5e00.0a14 int g5/2 ?

Hope to help

Giuseppe

Dear  Giuseppe,

But when I see the mac address of the multicast ip it does not start with 0100.5xxx.It starts with 02

Regards,

Sunil P

Hello Sunil,

>> But when I see the mac address of the multicast ip it does not start with 0100.5xxx.It starts with 02

that is not a correct multicast MAC address for an IPv4 multicast IP address.

But are you trying to implement microsoft network load balancing?

in that case a fake MAC address outside the correct range is used

if so, you just need to create static entries in CAM table not to use IGMP snooping

Hope to help

Giuseppe

Mohamed Sobair
Level 7
Level 7

Hi,

You will need (ip igmp static-group) command, once client joins a group , the process is fast switched  and more over, its introduces with new feature allows you to define multiple groups for multiple sources in a single command by configuring a class map.


Hae a look at the bellow link:

http://www.cisco.com/en/US/docs/ios/12_2sx/feature/guide/stgrpsxf.html

HTH,

Mohamed

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