First time here? Check out the FAQ!
THIS IS A TEST INSTANCE. Feel free to ask and answer questions, but take care to avoid triggering too many notifications.
Ask Your Question
0

snmp.time respective to retransmits

  • retag add tags

My operational case is when capturing SNMP packets and if the server detects no/slow response (TO) it will retransmits the same request ID, application will ignore TO response and keep trying (max3) until a response within TO is received

Wireshark when displaying snmp.time associates all the delayed responses to the last transmitted SNMP get request associated to the request ID

  1. packet 1 , id1 request get @ time 0 , snmp.time = - 30 seconds
  2. packet 2 , id1 request get @ time +10 seconds , snmp.time = - 20 seconds
  3. packet 3 , id1 request get @ time +20 seconds , snmp.time = ( no snmp.time as it is a get request )
  4. packet 4 , id1 response @ time + 25 seconds , snmp.time = 5 seconds
  5. packet 5 , id1 response @ time + 30 seconds , snmp.time = 10 seconds

  6. packet 6 , id1 response @ time + 35 seconds , snmp.time = 15 seconds

    I want (expect) packets 4-6 to have snmp.time (25,30,35)

Wireshark provide snmp.time to repeats get requests relative the last get request Wireshark provide snmp.time for responses (multiple) to last snmp get request

Is there a way to configure to display differently?

nfldson's avatar
1
nfldson
asked 2023-04-24 14:48:44 +0000, updated 2023-04-24 14:53:44 +0000
edit flag offensive 0 remove flag close merge delete

Comments

add a comment see more comments

1 Answer

0

rfc3416: Version 2 of the Protocol Operations for the Simple Network Management Protocol (SNMP)

However, in order to calculate the round trip time for transmission and processing of a request-response transaction, the application needs to use a different request-id value on a retransmitted request. The latter strategy is recommended for use in the majority of situations.

With a non-unique request ID in all requests and responses, how do you know the responses are not arriving out of order?

The value of the request-id field in a Response-PDU takes the value of the request-id field in the request PDU to which it is a response. By use of the request-id value, an application can distinguish the (potentially multiple) outstanding requests, and thereby correlate incoming responses with outstanding requests. In cases where an unreliable datagram service is used, the request-id also provides a simple means of identifying messages duplicated by the network. Use of the same request-id on a retransmission of a request allows the response to either the original transmission or the retransmission to satisfy the request.

Chuckc's avatar
3k
Chuckc
answered 2023-04-24 16:55:36 +0000
edit flag offensive 0 remove flag delete link
more

Comments

There would be no guarantee , application is tracking responses. Also if packet(s) were lost , would result in some RT not being able to be calculated. In this case response is delayed to server and can not track specific RT in csv export.

nfldson's avatar nfldson (2023-04-25 22:36:31 +0000) edit
more
  • delete
add a comment see more comments

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account. This space is reserved only for answers. If you would like to engage in a discussion, please instead post a comment under the question or an answer that you would like to discuss.

Add Answer