[c-nsp] Sup2 (Not Sup2T) on a 6513 (NON-E)

[Tim Stevenson]

Hi Nick, please see inline below:

At 12:32 PM 9/9/2016  Friday, Nick Cutting asserted:
>Good afternoon Lords of the Layers,
>
>Anyone remember far back enough to answer two questions on the SUP2 
>supervisor on an original (NON-E) 6513 chassis?
>
>It seems the online cisco documentation doesn't go further back than 
>the SUP 32 - it's very hard to find a datasheet for this.
>
>Mod Slot Ports Module-Type               Model               Sub Status
>--- ---- ----- ------------------------- ------------------- --- --------
>1   1    2     1000BaseX Supervisor      WS-X6K-SUP2-2GE     yes ok
>
>The layer 2 is CatOS and the layer 3 is IOS.
>
>A client has a couple of these switches I am trying to phase out, 
>and was wondering two things, throughput related.
>
>The layer 2 switching engine trunks all traffic destined to be 
>routed on the switch, up to an internal port on the SUP known as 
>15/1 -> then over to the layer 3 IOS to be routed on the SVI.


No, not really. 15/1 is for traffic *destined* to the router, not 
traffic the router will L3 switch. That's done more or less exactly 
the same as in more current sups, ie, hardware-based FIB lookup.


>Spanning tree has a value of 4 for the cost of this link - and in 
>spanningtree IEEE - this is 1 gig.
>
>Port                     Vlan Port-State    Cost      Prio Portfast Channel_id
>15/1                     11   forwarding            4   32 enabled  0
>
>Does this mean that anything that is routed - maxes out at 1 gig on 
>this platform? Or is the spanning tree value here arbitrary - and 
>the backplane faster than this? - I thought the backplane of the SUP 
>2 was 32 gig - is this for switching and routing - or just switching?


Again, this is just the inband port. It's treated on the switch side 
as 'just another port in STP'. It looks more or less like a router on 
a stick - but with the very important distinction mentioned above, 
that transit traffic is h/w switched, not passed over this interface.



>Also when configuring etherchannel on the CatOS switching engine - 
>it mentions a warning message about maximum speed being 1 gig - I 
>imagine this is just talking about a single flow - and multiple 
>flows will be load shared as normal?


This is a totally different problem space, which as you mention in 
your follow up message is related to the 6148-GE-TX LC you are using. 
I don't think I'm allowed to talk about it in quite the same language 
that Gert does ;) but this card is heavily oversubscribed, and has 
this particular limitation because of the internal architecture, 
which is 8 x 1G connections to 8 x 8:1 oversubscribed port ASICs.

So it is actually talking about the TOTAL port-channel bandwidth and 
not per flow or anything, but the limit is 1G *per port group* not 
per channel. Couple examples:

1. if you put 1 port in each port group in the channel then you could 
get 8G thruput theoretically, assuming no other ports in any of the 
port groups were passing traffic

2. if you put all 8 ports in one port group, you'd only get 1G of thruput


Hope that helps,
Tim



>Any insight would be greatly appreciated.
>
>Thank you,
>Nick Cutting
>
>
>
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Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Distinguished Engineer, Technical Marketing
Data Center Switching
Cisco - http://www.cisco.com
+1(408)526-6759