EtherChannel restrictions on 6509 WS-6548-GE-TX cards

[arathyram]

Hi All

Re: Etherchannel on 6509 using WS-6548-GE-TX line cards and IOS. Am running into contradictory answers from CCO doc, and TAC. Appreciate if anyone has come across this.

I understand the 65xx line cards are prone to oversubscription (8:1). The ASIC on these is 6 ports per ASIC, with a 1GB connection into the backplane. So, if we setup adjacent ports in a port channel (or for that matter even use adjacent ports at Gig speed) - the throughput into the backplane is limited to 1G. Am i missing something here ?

If running CATOS 8.2.1 with firmware updates, apparently this is not an issue. TAC mentioned this is a known issue with the 65xx line cards.

Has anyone setup etherchannel on the 65xx modules and had to take the above into account. Tentative plan was for me to use

PO1 - 1/1, 2/1, 3/1, 4/1

PO2 - 1/9, 2/9, 3/9, 4/9

PO3 - 1/17, 2/17, 3/17, 4/17

But, again inbetween ports 1/2, 1/3 will be a PO4 to a smaller 4948 (so i dont see a point in getting too tied up with the oversubscription issue as i can't waste # of ports).

any thoughts, appreciate

aram

[jbrenesj]

Actually 8:1 means 8 ports per ASIC so yes, consecutive groups of 8 ports share just 1GB backplane connection.

This is how it goes in regards to CatoS and the 8.2 deal:

The WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6148-GE-TX, and WS-X6148V-GE-TX modules have a limitation with EtherChannel.

You receive a message on the maximum throughput when you add a port of this module to EtherChannel.

C6500> (enable) set port channel 3/5,4/5 mode on

Adding a WS-X6148-GE-TX port to a channel limits the channel's bandwidth to a maximum of 1Gig throughput

--------------------------------------------------------

The 1 Gig restriction is a hardware limitation on the modules. If you

want 8 GE ports at line rate, then you will need to use a WS-X6748-GE-TX

(which requires Sup720).

From the CatOS 8.x Release Notes :

The WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6148-GE-TX, and WS-X6148V-GE-TX

modules do not support the following:

­More than 1 Gbps of traffic per EtherChannel

********************************************** <<<<<<<<<<<<<<

Note With software release 8.2(1) [and newer], due to firmware enhancements,

the oversubscription problems associated with EtherChannel are no longer an

issue with the WS-X6548-GE-TX module.

********************************************** <<<<<<<<<<<<<<

This means that you can have let's say ports 1 and 9 on the WS-X6548-GE-TX working in a 2Gb channel after 8.2(1) or in IOS <<<<<<<

This is your case so PO1 (g1/1, 2/1, 3/1 and 4/1) sounds really good to me and if the remaining 7 ports of the group won't connect to anything consuming important bandwidth then you can use them.

[arathyram]

Thanks for the confirmation. Inline with what i've been gathering thus far.

Looks like safest option is to go CATOS.

This is at the DC distribution layer. So, say, if i do IOS, and PO1 (g 1/1, 2/1, 3/1, 4/1) to 2xCore swithces - that is good which you agree too.

But, a sidebar issue is that the in between ports such as 1/2, 1/3, 1/4 .. etc - these will also have PO channels to server access switches back into the DC. So, in essense they will also be connecting to bw hogs (though not into the Core layer).

Hmm .. stuck with CATOS looks like to overcome the 65xx limitation ?

TIA

aram

[Edison Ortiz]

Hmm .. stuck with CATOS looks like to overcome the 65xx limitation ?

No need to:

"Release 12.2(17b)SXA and later releases provide support for more than 1 Gbps of traffic per EtherChannel on the WS-X6548-GE-TX (and voice-power daughtercard equipped) switching modules. "

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/release/notes/OL_4164.html

HTH,

__

Edison.

[jbrenesj · Accepted solution]

On my previous post it said:

after 8.2(1) or in IOS <<<<<<<

Thanks, Jorge