Multicast issue while downstreaming

[habeebuddin786]

Hi Folks,

I am facing some issue with the multicasting.

Issue reported as: - Downstream is not happeneing from the different ports on the server in VM machine.

Analysed: - Multicast server which is sending multicast traffic is not receiving on another server (receiver) when they are connected to different interface in th same VLAN 2. This is the VMware environment. When the receiver machine is moved to the same blade where the sender server is reciding the muticast video is able to receive. Once it moved to the different balde the video hangs up. These servers are connected to the same switch cisco 3750G using software as (Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(25)SEE3). This seems to be an issue in the switch configuration. I am new to the multicasting and please let me know how whould i configure the multicasting on the 3750G switch.

sh ip igmp snooping vlan 2

Global IGMP Snooping configuration:

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

IGMP snooping              : Enabled

IGMPv3 snooping (minimal)  : Enabled

Report suppression         : Enabled

TCN solicit query          : Disabled

TCN flood query count      : 2

Last Member Query Interval : 1000

Vlan 2:

--------

IGMP snooping                       : Enabled

IGMPv2 immediate leave              : Disabled

Explicit host tracking              : Enabled

Multicast router learning mode      : pim-dvmrp

Last Member Query Interval          : 1000

CGMP interoperability mode          : IGMP_ONLY

sh run int vlan 2

Building configuration...

Current configuration : 77 bytes

!

interface Vlan2

ip address 10.2.1.250 255.255.252.0

no ip redirects

end

sh run int gig 1/0/15           -----------------> (Server which is sending multicast traffic)

Building configuration...

Current configuration : 145 bytes

!

interface GigabitEthernet1/0/15

switchport access vlan 2

switchport mode access

spanning-tree portfast

spanning-tree bpduguard enable

end

sh run int gig 1/0/12 ------------------------------------------> (Receiver which is supposed to receive multicast video)

Building configuration...

Current configuration : 145 bytes

!

interface GigabitEthernet1/0/12

switchport access vlan 2

switchport mode access

spanning-tree portfast

spanning-tree bpduguard enable

end

sh int gig 1/0/15

GigabitEthernet1/0/15 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 001c.f6a0.b28f (bia 001c.f6a0.b28f)

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

  5 minute input rate 347000 bits/sec, 337 packets/sec

  5 minute output rate 368000 bits/sec, 390 packets/sec

     0 watchdog, 154938684 multicast, 0 pause input --------------------> (multicast packets seen incremented when the sender server starts upstreaming)

     0 input packets with dribble condition detected

sh int gig 1/0/12

GigabitEthernet1/0/12 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 001c.f6a0.b28c (bia 001c.f6a0.b28c)

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

  5 minute input rate 74000 bits/sec, 79 packets/sec

  5 minute output rate 296000 bits/sec, 337 packets/sec

     0 watchdog, 690421049 multicast, 0 pause input  ------------------> (no changes in multicast packets seen when the sender server starts upstreaming)

     0 input packets with dribble condition detected

Thanks,

Ahmed

[Giuseppe Larosa]

Hello Ahmed,

with IGMP snooping enabled a receiver must sends IGMP reports in order to be placed in the list of ports of vlan2 to which the stream has to be sent

IGMP snooping tries to optimize the forwarding of multicast within a VLAN/broadcast domain

so you should check if:

there is a device sending IGMP queries on vlan 2, without such device the hosts will not send IGMP reports every X seconds.

so you need a multicast router with PIM enabled on vlan 2. it can be the C3750 itself

ip multicast routing

interface vlan 2

ip pim sparse-dense-mode

if you want to run multicast on vlan 2 only you may need something else like an IGMP querier, that is only the function of sending IGMP queries in order to make IGMP snooping happy

However, given your switch model and the IOS image that is quite old I don't think igmp querier is supported on it

Edit:

igmp querier looks like supported in 12.2(25)SEE

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_see/configuration/guide/swigmp.html#wp1193337

so you should have also this option

Hope to help

Giuseppe

[habeebuddin786]

Hi Giuseppe,

Appreciate your response. Its very valuable information. Let me try configuring as per your suggestion and let you the result.

Thanks,

-Ahmed

[habeebuddin786]

Hi Giuseppe,

I think the following commands are not supportive on my current 3750G switch.

ip multicast routing

interface vlan 2

ip pim sparse-dense-mode

I only see the option of querier is available on the switch.

If i enabled the querier on the switch what source IP i need to give. I mean will the source IP is the sender server IP address or the SVI of VLAN2?

kindly suggest.

Thanks

Ahmed

[Giuseppe Larosa]

Hello Ahmed,

I see it depends on the type of image (and SDM template may be)

the source used for the IGMP queries will be that of SVI Vlan 2 your understanding is correct

Hope to help

Giuseppe

[habeebuddin786]

Hi Guiseppe,

I tried following commands globally on the 370G switch but still the downstreaming didn't work on the different blades.

# ip igmp snooping vlan 2

# ip igmp snooping querier address

Should i have to upgrade the switch with new IOS version which comaptible to IGMP v3.? Below is the igmp snooping output:

sh ip igmp snooping vlan 2

Global IGMP Snooping configuration:

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

IGMP snooping              : Enabled

IGMPv3 snooping (minimal)  : Enabled

Report suppression         : Enabled

TCN solicit query          : Disabled

TCN flood query count      : 2

Last Member Query Interval : 1000

Vlan 2:

--------

IGMP snooping                       : Enabled

IGMPv2 immediate leave              : Disabled

Explicit host tracking              : Enabled

Multicast router learning mode      : pim-dvmrp

Last Member Query Interval          : 1000

CGMP interoperability mode          : IGMP_ONLY

Kindly suggest

Thanks

Ahmed

[Giuseppe Larosa · Accepted solution]

Hello Ahmed,

if your servers send out an IGMPv3 report , the IGMP snooping code may be not able to understand the message and so the stream is blocked.

To verify if this is the issue you can temporarly disable IGMP snooping on vlan 2.

If you want to control the flooding of this multicast stream within Vlan 2 broadcast domain layer2 ports you need IGMP snooping.

IGMP snooping is performed in hardware by an ASIC chip, so an upgrade of IOS may be not enogh to fix this.

According to configuration guide some support of IGMPv3 is present

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_25_see/configuration/guide/swigmp.html#wp1089644

>>The switch supports IGMPv3 snooping based only on  the destination multicast MAC address. It does not support snooping  based on the source MAC address or on proxy reports.

Hope to help

Giuseppe