Sunday, April 19, 2015

How to troubleshoot MDS9513 Add ISL to Port Channel

As a networking adviser in 3Anetwork, I have recieved so much mails from  MDS9513 users about Advisorying a problem when add a new ISL to an existing Port Channel config.
I am here to answer the typical parts to help users :
The ISL port is up state and correctly configured like another ports in port channel.
Looks bellow the error:
MDS1300M6A# show port-channel summary
------------------------------------------------------------------------------
Interface                 Total Ports        Oper Ports        First Oper Port
------------------------------------------------------------------------------
port-channel 1                 4                 4                  fc12/48
port-channel 2                 2                 2                  fc6/47
MDS1300M6A# show port-channel database
port-channel 1
    Administrative channel mode is active
    Operational channel mode is active
    Last membership update failed: port not compatible [Resources Unavailable]
    First operational port is fc12/48
    4 ports in total, 4 ports up
    Ports:   fc12/48  [up] *
             fc10/48  [up]
             fc11/48  [up]
             fc9/48   [up]


You can settle it down this way:By default interfaces that are put into a SAN port channel must have rate-mode dedicated set. I personally think this is over kill and wastes resources.
The work around that I have used many times is to use a shared mode port-channel. To do this you must first create the port-channel, set the switchport mode to F, channel mode active and set the rate-mode to shared and then add the interfaces to it using the force keyword. Here is an example config
feature npiv
feature fport-channel-trunk
interface port-channel 11
  channel mode active
  switchport mode F
  switchport description SAN Port Channel to UCS 6140-A fc2/1-6,fc3/1-6
  switchport rate-mode shared
interface fc1/1
  switchport description UCS 6140-A fc2/1
  channel-group 11 force
  no shutdown
interface fc1/2
  switchport description UCS 6140-A fc3/1
  channel-group 11 force
interface fc1/7
  switchport description UCS 6140-A fc2/2
  channel-group 11 force
  no shutdown
interface fc1/8
  switchport description UCS 6140-A fc3/3
  channel-group 11 force
  no shutdown
interface fc1/13
  switchport description UCS 6140-A fc2/3
  channel-group 11 force
  no shutdown
interface fc1/14
  switchport description UCS 6140-A fc3/4
  channel-group 11 force
  no shutdown
When a port is in rate-mode shared there are no guarantees on how much of the port group bandwidth the port will actually have access to. Depending on the line card there are port groups made of up 6 ports, all 6 ports share 12-13GB of bandwidth. When a port in a port-group is placed in dedicated mode it is gauranteed 4/8G depending on the line card and SFP.

Take a look at this config guide

And more related latest product’s supporting solutions in


No comments:

Post a Comment