IGMP Setup? 3

[dvtestguy]

Trying to set up IGMP on a 6506 for the first time, and want to know if anyone has any real-time configs as an example? I'm looking to configure from the switch and down to the port level with joins, leaves, etc....any ideas?

Thanks!

 

[UnaBomber]

Its easy to set up:

http://www.cisco.com/warp/public/473/22.html#igmprouter

You setup Pim on your router, (or your RP, in your case), setup IGMP snooping, or cgmp (in a cisco enviroment) on your layer 2 switches.

Pim enables multicast routing, igmp snooping/cgmp allows hosts to join and leave the multicast sessions from a layer 2 perceptive.



UnaBomber
ccnp mcse2k

 

[dvtestguy]

Is there a particular IP address range that is needed to join IGMP? Guessing that I'd need an m-cast range?

 

[UnaBomber]

To join or leave a multicast the client issues a join/leave IGMP membership report message to the router on his subnet.

UnaBomber
ccnp mcse2k

 

[dvtestguy]

So the config on my 6506 switch would be? I guess I'm still missing what IP range on this? Any 239 address?

config# int vlan 741
config-if# ip igmp snooping querier

int g1/7
ip address ????
switchport access vlan 741
switchport trunk encapsulation dot1q
switchport mode access

 

[KiscoKid]

IANA allocate 239.0.0.0 through to 239.255.255.255 for multicast use within internal Enterprise networks.

 

[UnaBomber]

At layer 2 all you need is IGMP Snooping
At layer 3 you need to configure:

PIM (go for Sparse-Dense Mode)
IGMP
IP Multicast routing

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_c/1cprt1/1cmulti.htm#4919

Here is a great link breaking down the whole configuration steps. As I said its not so difficult, but you need to get your head around the concept. You do not need to configure interfaces with Multicast addresses, all your interfaces need to be configured with Unicast address, and your unicast network needs to work (routing).

UnaBomber
ccnp mcse2k

 

[helpdeskdan]

If it's local to one network you should only need igmp snooping if I remember correctly. You only need a router/PIM if you need to route it to other networks. The switch will pay attention to the IGMP join messages; it doesn't care that the router will ignore them.

 

[dvtestguy]

helpdeskdan,

I have the following setup...
C75xx --- C65xx --- Test Probe

So if I have a single subnetted network (for lab purposes only) and have some test probes capable of joining an IGMP session (directly connected to the 65xx switch), what would I need to configure for that switch? I don't think I need to configure anything on the 75xx Router?

 

[helpdeskdan]

Sure, I'll answer this so unabomber can answer some harder questions.

What is it you wish to do? Just use multicasting on your local subnet? Source and destination on the same subnet? That's easy. It requires NO configuration. Multicasting only requires configuration if you need to send it to OTHER SUBNETS. Your router will ignore the multicasts and that is what you want.

Now, igmp SNOOPING is a good thing if you want to limit the multicasting inside your subnet. Do you need to? Not at all - the other workstations will happily ignore the multicasts! Won't even slow them down - it is ignored at layer 2. (Think it happens in hardware - not sure, interesting question) It's just a nice thing to have - why send traffic to ports it doesn't need to go to?

On catos it's 'set igmp enable'. On ios, it's 'ip igmp snooping'. It's really that easy.

 

[dvtestguy]

I'm looking to have the test probes be able to join/leave/report/querie on a specific vlan. I'm using a IP traffic generator (MPEG/UDP streams) with associated MAC, IP, etc onto the 65xx switch, and want the probes to be able to join them. Just not sure if enableing IGMP is as simple as that? I thought I needed to configure at the VLAN interface or some IP address association to the actual ports in question?

Yes, mcast on the local subnet. Am I to setup snooping on each vlan int or the entire switch?

Thanks...

 

[helpdeskdan]

Entire switch. Should work just fine. Give it a try.

 

[dvtestguy]

All,...[Traffic Generator--> 6506 <-VTP-> 4948 <--Host].

Still not seeing joins/leaves properly, and not seeing traffic on the streams?

My configs appear ok, and see the Cisco General Query sent and the IGMP v2 Membership Report from the 10.115.62.5 host. I'm using a traffic generator (see bottom for config) for the streams and do not see them passing any traffic. Anything I'm missing in my configs?

Cisco6500IOS#sh ip igmp sn mr
vlan ports
-----+----------------------------------------
620 Router


Cisco6500IOS#sh ip igmp gr
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
239.255.33.1 Vlan620 01:28:41 00:02:47 10.115.62.5
239.255.33.2 Vlan620 01:01:31 00:02:49 10.115.62.5
239.255.33.4 Vlan620 01:01:29 00:02:51 10.115.62.5
239.255.33.5 Vlan620 01:01:27 00:02:53 10.115.62.5

Cisco6500IOS#sh ip igmp int vlan 620
Vlan620 is up, line protocol is up
Internet address is 10.115.62.2/28
IGMP is enabled on interface
Current IGMP host version is 2
Current IGMP router version is 2
IGMP query interval is 60 seconds
IGMP querier timeout is 120 seconds
IGMP max query response time is 10 seconds
Last member query response interval is 1000 ms
Inbound IGMP access group is not set
IGMP activity: 11 joins, 7 leaves
Multicast routing is enabled on interface
Multicast TTL threshold is 0
Multicast designated router (DR) is 10.115.62.2 (this system)
IGMP querying router is 10.115.62.2 (this system)
No multicast groups joined
IGMP snooping is globally enabled
IGMP snooping is enabled on this interface
IGMP snooping fast-leave is disabled on this interface
IGMP snooping querier is enabled on this interface
IGMP snooping last member query interval on this interface is 1000 ms

ip multicast-routing


interface GigabitEthernet3/8
description IGMP Traffic
speed nonegotiate
switchport
switchport access vlan 620
switchport trunk encapsulation dot1q
switchport trunk allowed vlan none
switchport mode access
no cdp enable
spanning-tree portfast trunk
end

----------

Cisco4948#sh ip igmp sn mr
Vlan ports
---- -----
620 Gi1/47(dynamic), Router

isco4948#sh ip igmp g
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
239.255.33.1 Vlan620 04:54:04 stopped 10.115.62.5
239.255.33.2 Vlan620 00:23:11 stopped 0.0.0.0
239.255.33.3 Vlan620 00:22:49 stopped 0.0.0.0
239.255.33.4 Vlan620 00:22:46 stopped 0.0.0.0
239.255.33.5 Vlan620 00:22:44 stopped 0.0.0.0

Cisco4948#sh ip igmp int vlan 620
Vlan620 is up, line protocol is up
Internet protocol processing disabled


interface GigabitEthernet1/7
description 10.15.12.62 IGMP Host
switchport access vlan 620
switchport trunk encapsulation dot1q
switchport mode access
switchport nonegotiate
speed auto 1000
no cdp enable
spanning-tree portfast trunk
end


-----------

Generating Traffic
Source
MAC 00-10-10-11-01-01
MAC Increment 0-0-0-0-0-0
IP Address 10.115.62.2
IP Increment 0.0.0.1
Port # 2000
Port Increment 1

Destination
MAC 01-00-5E-01-01-01
MAC Increment 0-0-0-0-0-1
IP Address 239.255.33.1
IP Increment 0.0.0.1
Port # 3000
Port Increment 1

Number of streams 5

 

[helpdeskdan]

Are you sure your clients and traffic generator can connect? Are you sure your trunk is setup correctly?

Plug the source and dest. into the a switch and make sure that works first. No configuration required.