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Not seeing iSCSI traffic in an Infiniband RRoCE capture without initial ConnectRequest/ConnectReply/ReadyToUse sequence

asked 2020-09-16 07:58:40 +0000

updated 2020-09-17 06:52:57 +0000

Guy Harris gravatar image

I encounter some problem, when I use the iSCSI RDMA solution, use the ibdump to capture the package and use Wireshark to do analysis. But, if there is no login package in the dump, then Wireshark will not filter the iSCSI Protocol. If there is login package in the dump, then Wireshark can filter and show the iSCSI Protocol.

Do you know if there is any method to ask Wireshark to show the data payload as iSCSI Protocol by manual?

Thanks, Billy

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The Wireshark Wiki entry for iSCSI.

Do you know what version of the protocol is in the capture?

Edit: Update Wiki link to new wiki at GitLab.

Chuckc gravatar imageChuckc ( 2020-09-16 14:26:36 +0000 )edit

I upload the two pcap. Please refer to below link. The "rdma_logout_only.pcap", which capture the iSCSI logout process only, and the "rdma_login_out.pcap" which capture the iSCSI login and logout process. Then Wireshark can identify the iSCSI Protocol in the "rdma_login_out.pcap", but it can not identify the iSCSI Protocol in the "rdma_login_out.pcap" which does not include the iSCSI login package.

rdma_logout_only.pcap: https://drive.google.com/file/d/1HnWX...

rdma_login_out.pcap https://drive.google.com/file/d/1Xf26...

billychiu gravatar imagebillychiu ( 2020-09-17 05:04:30 +0000 )edit

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answered 2020-09-17 06:26:41 +0000

Guy Harris gravatar image

updated 2020-09-17 06:54:44 +0000

But, if there is no login package in the dump, then Wireshark will not filter the iSCSI Protocol.

Do you mean the iSCSI login, or the sequence of Infiniband messages preceding the iSCSI login, setting up a connection?

What appears to be missing is not the iSCSI login, it's the Infiniband ConnectRequest/ConnectReply/ReadyToUse sequence before the iSCSI login. With that missing, even if there is an iSCSI login, Wireshark won't recognize it. (Tested by using editcap to remove those first 3 packets from the capture with the login and trying to read it; even though it had the iSCSI login, none of the iSCSI traffic, including the login, was dissected a iSCSI.)

Do you know if there is any method to ask Wireshark to show the data payload as iSCSI Protocol by manual?

What's needed here is a way to show the payload as iSCSI Extensions for RDMA.

The general way of doing that in Wireshark is the "Decode As..." mechanism. Try clicking on the first packet in that capture, select Analyze > Decode As..., click the "[+]" button to add a new entry, make that entry decode "Infiniband Payload" as "iSER" ("Field" column is "Infiniband Payload", "Current" column is "iSER"), and click "OK". (That worked on both the logout-only capture and on the capture I constructed by stripping the ConnectRequest/ConnectReply/ReadyToUse sequence from the login/logout capture.)

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Thank you, Guy. It works perfectly.

billychiu gravatar imagebillychiu ( 2020-09-17 08:38:44 +0000 )edit

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Asked: 2020-09-16 07:58:40 +0000

Seen: 308 times

Last updated: Sep 17