Multicast - PIM troubleshooting

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Hello,
We have a location where our tech is reporting he cannot ghost image a computer lab (roughly 20 PCs). At that site we have a core of x670v-48x and x460-48p switches.  Code is at 15.5.3.4 patch 1-5

We have pim setup in this fashion:

configure pim add vlan "IDF" sparse 
configure pim add vlan "MDF" sparse
configure pim add vlan "JVloop" sparse
configure pim crp vlan "JVloop" "RP-list" 30
enable pim
configure pim cbsr vlan "JVloop"


When I issue the show pim command;  I see the BSR elected and all the appropriate vlans rifms, with the JVloop rifmsc

Our RP-list.pol file is 
entry rp-list {        if match any{
        }
        then {
                nlri 239.0.0.0/8;
                nlri 224.0.0.0/8;
        }
}

Igmp Snooping Flag            : forward-all-routerIgmp Snooping Flood-list      : none
Igmp Snooping Proxy           : Enable
Igmp Snooping Filters         : per-port



As a test, our tech plugged all the computers into a dumb switch and was able to mulitcast fine.  He cannot multicast when he's connected to the extreme stack.   When he is connected to the extreme stack, the clients are able to join the ghost server, but when he hits send to send them their images, it just spins then fails.

I've done the old stare and compare with other sites where I have been told multi-casting works fine, and I can't see a configuration difference.

I guess I'm looking for suggestions on what to try / tweak / look for?

Thank you
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Sarah Seidl

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Posted 3 years ago

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Michael Suggs

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im no PIM guru by any means, but if you run this command do you see the join request?

TOC-X460.24 # sh pim cache 224.1.100.21
Index  Dest Group      Source             InVlan   Origin
[0000] 224.1.100.21    192.168.1.1 (WR)   Cspire-Chicago Sparse
       Entry timer is not run; UpstNbr: 10.1.0.1
       EgressIfList =  Video-10Gig(0)(FW)(DM)(N)

[0001] 224.1.100.21    10.99.2.4 (S)      Cspire-Chicago Sparse
       Expires after 186 secs UpstNbr: 10.1.0.1
       RP: 192.168.1.1 via 10.1.0.1 in Cspire-Chicago
       EgressIfList =  Video-10Gig(0)(FW)(DM)(N)

is the PC on the same subnet as the network.  vlan?

if so you may try this command to the multicast he is pulling. basically forcing a join.

configure igmp snooping vlan "Cspire-Chicago" ports 34 add static group 224.1.2.21

  is there a route to the source of the MC?

show iproute
#s   192.168.1.1/32     10.1.0.1        1    UG---S-um--f- Cspire-Chicago 194d:11h:31m:6s

hope some of these ideas will help,
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Sarah Seidl

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Thank you, I'll coordinate with our tech and schedule time to look at what you recommended. 
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Mike D, Alum

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Hello Sarah,

In addition to checks at the router, your tech will want to verify ttl at the ghost server.  
Ghost default ttl should be enough for most small to medium networks but verifying this item should be on the checklist. 

Mike
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Sarah Seidl

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Thank you, I will be sure to ask him that.
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David Coglianese, Embassador

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What this issue resolved?

I have a similar issue.

They can Ghost PC on the same VLAN but cannot Ghost across VLANs.

The PIM dense config looks good and a Multicast traffic test tool installed on the same server as Ghost can send traffic to PCs on other VLANs.

Packet captures at both the port were the Server connects and were the client connect appear to show multicast traffic flowing but the Ghost session never progresses.

Any ideas would be greatly appreciated.
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Sarah Seidl

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We confirmed and reprogrammed PIM, everything looked right.

The ultimate fix was a reboot of the stack after hours.

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David Coglianese, Embassador

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Thanks for the response.

I'm dealing with a BDX8, we think the issue is with the clients.
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Brandon Clay, Escalation Support Engineer

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Hi  David,

I generally use the UDP multicast test tool found at the following link if I'm testing in the lab.

http://members.home.nl/hbthouppermans/Skybuck/

You could use this in the network to see if you are able to get a stream routed from the server to client VLANs. If you are, then it looks like the network side is good and any issues may be client side.
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David Coglianese, Embassador

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Brandon,

That is the same tool we use, and in this case it works fine. It is just Ghost that fails, we have been trying to figure out if there differences between the the steams that could make one forward and the other not. 

My latest WireShark captures seem to show everything working as expected but when I look at the logs on Ghost it is stuck in a re-transmit loop. 

Thanks,

Ghost Log Level All  93736593 timed out after 1015 ticks

           Wait(1000) timed out after 1016 ticks

  93737609 Wait(1000) timed out after 1000 ticks

  93738609 Wait(65) timed out after 78 ticks
  93738687 Retransmit timeout

           S:         ACK     TAK             SEQ=4617902 ACK=347 WIN=57240 LEN=0 ADDR=10.10.5.108:7777
           Slow start threshold 2862
           Congestion window 2862

           Wait(1000) returned (R) after 0 ticks

           R:         ACK             TOK     SEQ=347 ACK=4615040 WIN=57240 LEN=0 ADDR=10.10.5.108:7777
           Recv would block

           Wait(1000) timed out after 1016 ticks
  93739703 Retransmit timeout
           Slow start threshold 2862
           Congestion window 2862
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Brandon Clay, Escalation Support Engineer

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Hmm, that does sound like a client issue with Ghost. I'm assuming you are mirroring the client port to take a capture? Do you see the stream making it all the way to the client when trying to use Ghost?
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David Coglianese, Embassador

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I believe so. Here are links to packet captures from last week if you want to take a look.
https://www.dropbox.com/s/wocd9mjtd3zwjn3/AHD1P116.1.pcapng?dl=0
https://www.dropbox.com/s/8350ie9550fme5x/AHE-SRV_P23_Mirror_Filtered.pcapng?dl=0

Thanks,