Re: IP Multicsting L3 Switch

DevNet Engineer · ‎08-06-2018

Hello everyone,

I have a problem receiveing a multicast stream on a same vlan. My toplolgy - attached too - is as following:

SW1: configured with one vlan (vlan 80) and two hosts (host for multicast stream and the other for receiving, Rcvr -01.

SW2: configured as RP

SW3: configured with another vlan(vlan 90), which is attached for Receiver-2 (Rcvr-2)

Routing protocol:RIPv2

IP Multicasting: pim sparse-mode

all interfaces are pim sparse-mode enabled, including SVIs

I can receive the stream on Rcvr - 02 (vlan 90)

but i can not receive the stream on Rcvr - 01 (vlan 80), which is in the same vlan as the multicast source.

it is only working when i disable the igmp snooping for that vlan (vlan 80), but in this case the multicast will be flooding, and then there is no use or Benefit from the pim sparse-mode

Any idea?

thanks

Joseph W. Doherty · ‎08-06-2018

"it is only working when i disable the igmp snooping for that vlan (vlan 80), but in this case the multicast will be flooding, and then there is no use or Benefit from the pim sparse-mode"

You're confusing flooding across networks (PIM-SM) vs. flooding ports with the same network (IGMP snooping).

Most likely reasons for your issue, either your receiver on the same VLAN isn't properly working with IGMP snooping or you've got something misconfigured. Insufficient information to comment further. (Posting the configs of your 3 switches might allow further help.)

DevNet Engineer · ‎08-07-2018

Hello Joseph,

Here is the configurations of the switches:

SW1:

ip multicast-routing

!
!
interface Ethernet0/0
switchport access vlan 80
switchport mode access
duplex auto
!
interface Ethernet0/1
switchport access vlan 80
switchport mode access
duplex auto
!
interface Ethernet0/2
no switchport
ip address 172.168.100.1 255.255.255.252
ip pim sparse-mode

!
interface Vlan1
no ip address
shutdown
!
interface Vlan80
ip address 192.168.80.1 255.255.255.0
ip pim sparse-mode
!
router rip
version 2
network 0.0.0.0
no auto-summary
!
ip pim rp-address 6.6.6.6

!
end

SW2:

ip multicast-routing

!
interface Loopback6
ip address 6.6.6.6 255.255.255.255
ip pim sparse-mode
!
interface Ethernet0/2
no switchport
ip address 172.168.100.2 255.255.255.252
ip pim sparse-mode
!
interface Ethernet0/3
no switchport
ip address 172.168.200.2 255.255.255.252
ip pim sparse-mode
!
interface Vlan1
no ip address
shutdown
!
router rip
version 2
network 0.0.0.0
no auto-summary
!
ip pim rp-address 6.6.6.6
!
end

SW3:

ip multicast-routing

!
interface Ethernet0/0
switchport access vlan 90
switchport mode access
duplex auto

!
interface Vlan1
no ip address
shutdown
!
interface Vlan90
ip address 192.168.90.1 255.255.255.0
ip pim sparse-mode
!
router rip
version 2
network 0.0.0.0
no auto-summary
!
ip pim rp-address 6.6.6.6

!
end

########

and down below is the Output of the command - Show ip mroute - for each switch:

SW1:

(*, 224.0.1.40), 00:23:21/00:02:45, RP 6.6.6.6, flags: SJCL
Incoming interface: Ethernet0/2, RPF nbr 172.168.100.2
Outgoing interface list:
Vlan80, Forward/Sparse, 00:23:19/00:02:45

SW2:

(*, 224.0.1.40), 00:18:21/00:02:43, RP 6.6.6.6, flags: SJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
    Ethernet0/3, Forward/Sparse, 00:16:20/00:02:56
    Ethernet0/2, Forward/Sparse, 00:16:29/00:02:45
    Loopback6, Forward/Sparse, 00:18:19/00:02:43

SW3:

(*, 224.0.1.40), 00:20:32/00:02:28, RP 6.6.6.6, flags: SJCL
Incoming interface: Ethernet0/3, RPF nbr 172.168.200.2
Outgoing interface list:
Vlan90, Forward/Sparse, 00:20:30/00:02:28

Thanks a lot

Joseph W. Doherty · ‎08-07-2018

I didn't notice any obvious errors in your configs.

What's the platform and IOS version for sw1?

DevNet Engineer · ‎08-07-2018

I am using i86bi-linux-l2-adventerprisek9-15.2d.bin on GNS3 2.1.8.

i just got now real gears ( two Catalyst 3750-X), I will do the same confgiurations and see the results.

I will try to use the IP Services Licence.

Thanks

Joseph W. Doherty · ‎08-07-2018

Ah, perhaps GNS has an issue with L2 multicast. Let's us know how it goes with your 3750s.

DevNet Engineer · ‎08-08-2018

Hi Joseph,

it works now, i can receive the multicast stream on all hosts. However, I don't understand the mroute table result, why the mutlicast source is joing the Group 239.255.255.250?

SW1:

(*, 239.255.255.250), 00:51:16/stopped, RP 2.2.2.2, flags: SJC
Incoming interface: GigabitEthernet1/0/11, RPF nbr 172.168.100.1
Outgoing interface list:
Vlan80, Forward/Sparse, 00:51:16/00:02:57

(192.168.90.20, 239.255.255.250), 00:04:25/00:01:09, flags: JT
Incoming interface: GigabitEthernet1/0/11, RPF nbr 172.168.100.1
Outgoing interface list:
Vlan80, Forward/Sparse, 00:04:26/00:02:57

(*, 230.0.0.230), 00:51:14/stopped, RP 2.2.2.2, flags: SJCF
Incoming interface: GigabitEthernet1/0/11, RPF nbr 172.168.100.1
Outgoing interface list:
Vlan80, Forward/Sparse, 00:51:14/00:02:57

(192.168.80.10, 230.0.0.230), 00:10:20/00:03:29, flags: FT
Incoming interface: Vlan80, RPF nbr 0.0.0.0
Outgoing interface list:
GigabitEthernet1/0/11, Forward/Sparse, 00:10:20/00:03:20, A

(*, 224.0.1.40), 00:51:26/00:02:15, RP 2.2.2.2, flags: SJPCL
Incoming interface: GigabitEthernet1/0/11, RPF nbr 172.168.100.1
Outgoing interface list: Null

sw1#show ip igmp membership

Channel/Group                  Reporter Uptime    Exp. Flags    Interface
*,239.255.255.250 192.168.80.20   00:59:55 02:56    2A    Vl80
*,230.0.0.230 192.168.80.20   00:54:44 01:59    2A    Vl80
*,224.0.1.40                   172.168.100.2   19:24:34 02:16    2LA    Gi1/0/11

Thanks

Joseph W. Doherty · ‎08-08-2018

First, it's good to read it works on the 3750 - confirms your configs (and my not seeing any issue with them).

Second, I would presume the 239.255.255.250 group is due to what the host is doing.