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Can we use management port to do Fast-Hello for VSS Dual-Active Detection

s.patsuwan
Level 1
Level 1

I use VS-S2T-10G and i would like to use VSS. I am thinking that i will use management port to do Fast-Hello for VSS dual active detection. Can it work ?

5 Replies 5

Arumugam Muthaiah
Cisco Employee
Cisco Employee

Hi Sompoj,

Is there any sepecific reason to use management port for dual-active detection? Once you configure fast hello dual-active mode will will automatically remove all existing configuration from the interface.

dual-active fast-hello - Uses special hello messages over a backup Ethernet connection. You can configure both detection methods to be active at the same time.

For line redundancy, Cisco recommends dedicating at least two ports per switch for dual-active detection.
For module redundancy, the two ports can be on different switching modules in each chassis, and should be on different modules than the VSL links, if feasible.


To use the dual-active fast hello packet detection method, you must provision a direct Ethernet connection between the two VSS chassis. You can dedicate up to four non-VSL links for this purpose When you configure fast hello dual-active interface pairs, note the following information:

  • You can configure a maximum of four interfaces on each chassis to connect with the other chassis in dual-active interface pairs.
  • Each interface must be directly connected to the other chassis and must not be a VSL link. We recommend using links from a switching module not used by the VSL.
  • Each interface must be a physical port. Logical ports such as an SVI are not supported.
  • Configuring fast hello dual-active mode will automatically remove all existing configuration from the interface and will restrict the interface to fast hello dual-active configuration commands.
  • Unidirectional link detection (UDLD) will be disabled on fast hello dual-active interface pairs.

Refer:

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/15.0SY/configuration/guide/virtual_switching_systems.html#wp1131059

Use of Management port
A hung Route Processor (RP) could lock up the console, leaving it impossible to recover or determine the state
of the switch with no way to login to it.

A solution in such critical situations is to have a `backdoor' access into the switch to help restore it. This is addressed on next-generation supervisor engines through a new processor called the Connectivity Management Processor (CMP), which exists in conjunction with the primary Route Processor (RP).

The CMP on the Supervisor Engine 2T supports a front panel 10/100/1000 management port.

Refer:

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/white_paper_c11-663635.html

Regards,

Aru

*** Please rate if the post is useful ***

Regards, Aru *** Please rate if the post useful ***

Hi Arumugam Muthaiah,

Thanks for you information.  In fact, i have SUP-2T-10G.   After i read your information, I cannot use management port interface on SUP-2T-10G to do fast hello.    Howerver, I think that i want to use GE-SPF port on SUP-2T-10G to do fast hello .  Can i use it ?

thanks

sompoj

Hi Sompoj,

Sorry for the late response. Yes, you can use GE-SPF on Sup-2T for the fast-hello. I verified on our Lab using the wih VS-S720-10G and configured fast-hello on SFP port which works fine.

VSS#sh switch virtual link
VSL Status : UP
VSL Uptime : 3 weeks, 1 day, 15 hours, 13 minutes
VSL SCP Ping : Pass
VSL ICC Ping : Pass
VSL Control Link : Te2/5/4


VSS#show switch virtual dual-active fast-hello
Fast-hello dual-active detection enabled: Yes

Fast-hello dual-active interfaces:
Port       Local State    Peer Port    Remote State
---------------------------------------------------
Gi2/5/1    Link up        Gi1/5/1      Link up 

Please see the below Cisco recommandation to implement fast-hello,

  • Each interface must be directly connected to the other chassis and must not be a VSL link. We recommend using links from a switching module not used by the VSL.
  • You can configure a maximum of four interfaces on each chassis to connect with the other chassis in dual-active interface pairs.
  • Each interface must be a physical port. Logical ports such as an SVI are not supported.
  • Configuring fast hello dual-active mode will automatically remove all existing configuration from the interface and will restrict the interface to fast hello dual-active configuration commands.
  • Unidirectional link detection (UDLD) will be disabled on fast hello dual-active interface pairs.

Regards,

Aru

*** Please rate if the post is useful ***

Regards, Aru *** Please rate if the post useful ***

I'm working on setting up a new VSS cluster and am trying to configure the fast-hello link.  I have one 10G VSL link on a WS-X6708-10GE and the second VSL link on the VS-S720-10G.  I'm trying to create the non-VSL dual-active fast-hello interface on one of the Gig uplink ports on the VS-S720-10G.  I've added the dual-active fast-hello to one of the Gig uplinks, but when I try to bring it up it complains about the module being in 10G only mode.

NA151-4472-R47-U22-S(config-if)#int gig1/5/3

NA151-4472-R47-U22-S(config-if)#no shut

HW-QOS: Switch 1 slot 5 in '10g-only' mode. Gi1/5/3 can't be unshut

Is this a limitation on that module? Anything I can find in the documentation indicates that all three Gig uplinks are active along with the 10G ports even in a redundant supervisor configuration.  Unfortunately the way these were ordered was to provide network services only so there are only service modules and one 10G switch module in each chassis.  I hate to waste a 10G connection between them just for the dual-active fast-hello.  I'm thinking it has to do with the 'mls qos 10g-only' that was added as part of the VSS configration?

I found where I can re-enable the Gig ports if I issue the 'no mls qos 10g-only' command, but it mentions I have to reconfigure any QoS on those ports.  Does that include the 10G that has the VSL on it?

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