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Fibre Channel (SAN)

Posts: 6
Registered: ‎11-08-2004

Brocade 7840 portshow RTT average

Hello Experts,


I would like to know the calculation logic of average RTT of portshow output.

How long the duration of this average?




B7840-2:admin> portshow fciptunnel 24

 Tunnel: VE-Port:24 (idx:0, DP0)
  Oper State           : Online
  TID                  : 24
  Flags                : 0x00000000
  IP-Extension         : Enabled


  Sender Stats         : 2204345 bytes / 7899 pkts /   58.00 Bps Avg
  TCP Bytes In/Out     : 189815566 / 190228905
  ReTx/OOO/SloSt/DupAck: 341 / 0 / 28 / 0
  RTT (min/avg/max)    : 1 / 1 / 1 ms   <=============== This "avg" value
  Wan Util             : 2.2%
  TxQ Util             : 0.0%

External Moderator
Posts: 5,594
Registered: ‎02-23-2004

Re: Brocade 7840 portshow RTT average

@Haruo Kato


see follow note about RTT


Delay, or latency, is the amount of time that it takes a packet of data to get from one point to another. Delay is often measured by sending a packet that is returned to the sender; the packets round-trip time (RTT) is considered the delay in the network. In an IP network, delay depends not only on distance, but also upon router hop count, router processing, and packet size. A reasonable rule of thumb to estimate delay is driving distance multiplied by 1.5.


For more details, i would suggest to consult BPMSNA ( Brocade Professional Mainframe Storage Networking Architect ) Web Based Training, here example in Chapter 10-28

Posts: 6
Registered: ‎11-08-2004

Re: Brocade 7840 portshow RTT average

Hi Antonio,


My question was not good.
I understand the meaning of RTT.
I would like to know the monitoring duration period of average RTT value when using portshow command with "--reset" option (time based set of statistics).



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