• Home
  • Archive
  • Disclosure
    • Disclaimer
    • Comment Policy
    • Privacy Policy
  • Just Three
  • Contact
    • Who Am I ?
    • What does Ethereal Mind mean ?

EtherealMind

Software Defined & Intent Based Networking

You are here: Home / Cisco / IOS: show tcp vty

IOS: show tcp vty

16th October 2014 By Greg Ferro Filed Under: Cisco, Operation

On Cisco IOS, this is a very useful command “show tcp vty xx” to show TCP statistics of the VTY session. If you think your terminal is running slow because of packet loss or delay then this command will provide visibility. The other cause is the CPU/Memory running slow if you don’t see any  errors on the TCP (as you can see below).

You will need to run the command for each VTY in use, but mostly I use for myself to check if its the network or the box.

It can also be useful for packet capture filtering of the console session since the source port of SSH Client is shown here.

If the link is lossy then look at the “datagrams” section and check the Smooth Round Trip Time (SRTT).

r1#sh tcp vty 0
tty66, virtual tty from host 192.168.10.130
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Local host: 10.216.4.10, Local port: 22
Foreign host: 192.168.10.130, Foreign port: 54596
Enqueued packets for retransmit: 1, input: 0 mis-ordered: 0 (0 bytes)
Event Timers (current time is 0x18C84473E):
Timer Starts Wakeups Next
Retrans 409 0 0x18C844865
TimeWait 0 0 0x0
AckHold 321 1 0x0
SendWnd 0 0 0x0
KeepAlive 824 0 0x18C853196
GiveUp 0 0 0x0
PmtuAger 0 0 0x0
DeadWait 0 0 0x0
iss: 2955761392 snduna: 2955805244 sndnxt: 2955805264 sndwnd: 65535
irs: 472603036 rcvnxt: 472609745 rcvwnd: 3908 delrcvwnd: 220
SRTT: 300 ms, RTTO: 303 ms, RTV: 3 ms, KRTT: 0 ms
minRTT: 4 ms, maxRTT: 401 ms, ACK hold: 200 ms
Flags: passive open, higher precedence, retransmission timeout
 keepalive running, nagle
TCB is waiting for TCP Process (139)
Datagrams (max data segment is 536 bytes):
Rcvd: 778 (out of order: 0), with data: 321, total data bytes: 6708
Sent: 503 (retransmit: 0, fastretransmit: 0), with data: 441, total data bytes: 43871
lontrm01#

 

 

 

About Greg Ferro

Human Infrastructure for Data Networks. 25 year survivor of Corporate IT in many verticals, tens of employers working on a wide range of networking solutions and products.

Host of the Packet Pushers Podcast on data networking at http://packetpushers.net- now the largest networking podcast on the Internet.

My personal blog at http://gregferro.com

Comments

  1. Pmormr says

    16th October 2014 at 22:08 +0000

    Well how nifty is that… thanks for pointing it out!

  2. chandlerweb says

    17th October 2014 at 06:40 +0000

    Many bloggers nowadays seem to focus on being ‘thought leaders’ . It’s nice to see some good old fashioned tips and tricks posts!

Network Break Podcast

Network Break is round table podcast on news, views and industry events. Join Ethan, Drew and myself as we talk about what happened this week in networking. In the time it takes to have a coffee.

Packet Pushers Weekly

A podcast on Data Networking where we talk nerdy about technology, recent events, conduct interviews and more. We look at technology, the industry and our daily work lives every week.

Our motto: Too Much Networking Would Never Be Enough!

Find Me on Social Media

  • LinkedIn
  • RSS
  • Twitter
  • YouTube

Return to top of page

Copyright Greg Ferro 2008-2019 - Thanks for reading my site, it's been good to have you here.

Opinions, Views and Ideas expressed here are my own and do not represent any employer, vendor or sponsor.Full disclosure