Re: VSS and PFC3A

Hi Martin,

Yes, that is why I specifically talked about a backup Ethernet
connection - life is so much easier with a direct Ethernet connection.
If you have a switch stack or chassis in the middle then you need to
enable Enhanced PAgP. This uses PAgP messaging over the MEC links in
order to communicate between the two chassis through a neighbor switch.
Note that the neighbor switch must support the PAgP enhancements. This
is only supported on the 3750, 4500, 6500 and 6500 VSS switches - each
has a minimum IOS required.

regards Andy

Martin Kiefer wrote:
> Hi.
>
> I agree with you both, a dual active link is a good thing to have in a VSS
> setup, but remember that Dual active detection does not work on a Cisco 3750
> stack. Most people I have seen are using the 6500 as either core or
> distribution with 3750s as either access or distribution switches, and that
> makes often things a bit more complicated if they wishes to use dual active
> detection.
>
> Best regards
> Martin
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> KRATTIGER Lukas
> Sent: 4. august 2009 20:13
> To: ccie_at_reid.it
> Cc: Ram Shummoogum; ccielab_at_groupstudy.com
> Subject: AW: VSS and PFC3A
>
> Hi Andy
> correct, I certainly do also not recommend deploying VSS without the
> "sync-link" but it's not a must.
> Your points are all correct.
> Cheers
> -Lukas
>
> ________________________________
>
> Von: Andy Reid [mailto:ccie_at_reid.it]
> Gesendet: Di 04.08.2009 18:32
> An: KRATTIGER Lukas
> Cc: Ram Shummoogum; <ccielab_at_groupstudy.com>
> Betreff: Re: VSS and PFC3A
>
>
> Well Lukas,
>
> I strongly disagree - I certainly do not recommend deploying VSS without the
> 'sync-link'.
> This 'sync-link' is known as VSLP dual-active fast-hello and it uses special
> hello messages over a backup Ethernet connection. Dual-active fast-hello is
> faster than IP BFD and does not require support from a neighbor switch.
> It is one of three mechanisms used by the virtual switching system in order
> to detect a dual-active scenario if the VSL fails.
> A VSL failure is important to protect against as both chassis become active.
> This can obviously have adverse effects on network stability because both
> chassis use the same IP addresses, SSH keys, and STP bridge ID.
> If a client still wishes to go ahead without the additional link, then I
> raise it as a risk which the client accepts before proceeding with the
> implementation. The only times this has been raised is when the chassis are
> some distance apart and the link has to be leased. At all other times the
> link should be implemented as standard if both chassis are within the same
> data-center.
>
> regards Andy
>
>
> KRATTIGER Lukas wrote:
>
> Hi Andy
> Your so called sync-link is not needed, this will run on the 10G VSL
> links.
> There is no requirement to have an additional 1G link between the
> chassis.
> A 1g link for dual-active detection would be helpfull but not
> required.
> Cheers
> -Lukas
>
> ________________________________
>
> Von: Andy Reid [mailto:ccie_at_reid.it]
> Gesendet: Di 04.08.2009 17:20
> An: KRATTIGER Lukas
> Cc: Ram Shummoogum; ccielab_at_groupstudy.com
> Betreff: Re: AW: AW: VSS and PFC3A
>
>
>
> Hi Ram,
>
> Remember if you have 10GE cards installed it is not possible to
> remove
> their DFC's as they come installed as standard, which leaves the
> upgrade
> supervisor option. Note that you cannot have two supervisors in the
> same
> chassis when switching to VSS mode (at least not at the current SXI
> release). Only one supervisor in each chassis is supported, and each
> must be a VS-S720-10GE-3C or VS-S720-10GE-3CXL. It is not possible
> to
> use an older supervisor in each chassis and use 10GE cards (such as
> the
> 4, 8 or 16 port versions).
> Don't forget that you also need a synchronization link between the
> two
> chassis once cut-over - this is usually a 1GE copper link if they
> are
> the same room - it does not carry client traffic but information
> such as
> keep-alives and state information.
>
> regards Andy
>
> KRATTIGER Lukas wrote:
>
>
> Hi Ram
>
>
>
> You are correct. The DFC, CFC are on the linecards. There
> are also
> limitations according to the daughter cards.
>
> The only VSS compatible Supervisor is the
> VS-S720-10GE-3C/XL. It's a
> Sup720 with 2x 10G and PFC3c on it. All other Sups are not
> able to do
> VSS.
>
>
>
> I hope this helps.
>
>
>
> Cheers
>
> -Lukas
>
>
>
> Von: Ram Shummoogum [mailto:rshummoo_at_ca.ibm.com]
> Gesendet: Dienstag, 4. August 2009 16:44
> An: KRATTIGER Lukas
> Cc: ccielab_at_groupstudy.com
> Betreff: Re: AW: VSS and PFC3A
>
>
>
>
>
> Thanks for getting back so fast.
>
> When you say remove the PFC3A and replace with CFC or
> DFC3c/DFC3cXL: Are
> you referring to the SUP720. I thought CFC and DFC are only
> for
> linecards.
>
> For the line cards I am good as they are new and are DFC3C.
>
> Thanks
>
>
>
>
>
>
> "KRATTIGER Lukas" <Lukas.KRATTIGER_at_nextiraone.ch>
> <mailto:Lukas.KRATTIGER_at_nextiraone.ch>
>
> 08/04/2009 10:38 AM
>
> To
>
> Ram Shummoogum/Quebec/IBM_at_IBMCA, <ccielab_at_groupstudy.com>
> <mailto:ccielab_at_groupstudy.com>
>
> cc
>
>
> Subject
>
> AW: VSS and PFC3A
>
>
>
>
>
>
>
>
> Hi Ram
>
> Just remove your PFC3A and replace it with a CFC or buy a
> DFC3c/DFC3cXL.
> These are your two options.
> A VSS will never work with distributed forwarding below 3c.
> Just as a side note: The linecards for your VSLs need to
> have a
> DFC3c/DFC3cXL on it.
>
> Cheers
> -Lukas
>
>
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Received on Wed Aug 05 2009 - 23:38:17 ART