["Deepti Nambiar" <deepti.nambiar@xxxxxxxxxxxxxxxxx>]

Title: Message

 

 

Hello people,

 

            I seem to share a similar problem against Cisco3750, while trying to analyse the MST BPDUs-Refer to pasted section(in blue) of the webpage below..Any idea exactly what seems to be the issue and what is the version of Cisco that would rectify this(send “nice” MSTP BPDUs !). The ethereal capture also shows Malformed pkt.

 

Esp this part seems to occur exactly:

“"CIST Internal Root Path Cost" and "CIST Bridge identifier" occupy

wrong positions.

CIST Remaing hops" seems to have 2 bytes instead of 1. “

 Pl get back to me asap.

MSTP (802.1q or 802.1s) BPDU from Cisco ?

by "thomas_finne" <"thomas_finne"@[EMAIL PROTECTED] > Aug 4, 2004 at 09:23 AM

Hi All,

Does any one here know what is Cisco 2950A sending out as MSTP Bpdus?

While CIST information seems to be OK, MST Extension has another &

unknown format.

The version 3 length field in the Cisco BPDU is in the wrong location: 

it occupies the same location as the format selector defined in the

802.1s.

It seems, that the 16 bytes configuration digest in the BPDU from Cisco 

does not follow the recommendation of the 802.1s.  They have different 

values compared with those value shown in 802.1s Table 13-2.  So Cisco 

may not use HMAC-MD5 or the signature key as specified in 802.1s 13-7 

(4), and Table 13-1.

"CIST Internal Root Path Cost" and "CIST Bridge identifier" occupy

wrong positions.

"CIST Remaing hops" seems to have 2 bytes instead of 1.

I have not discovered MST Configuarion Messages because of problems

above.

I was discovering CISCO bridge *C3550 Software (C3550-I5Q3L2-M),

Version 12.1(12c)EA1* by Ethereal 0.10.5

 

 

 Thanks a ton,

Deepti

 

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