[c-nsp] Cisco 3750G backplane throughput

[Nick Cutting]

Use this command:

sh platform pm platform-block

Should be one ASIC per 24 ports, so a TS should have 1 asic for the normal ports and one for the SFP's.
On a my 48portTS, the SFP's are shared across the two normal ASIC's (48 copper ports)

I just removed my lab 3560g-24TS so I can't be 100 percent sure on the ASIC distribution.  I think it had 1 asic for the 24 copper and one for the sfp's.

How is your LAG traffic distribution?  You need many different flows to get much out of a LAG.
It is harder to get bandwidth out of the LAG than be outputted dropped by the ASIC, what I mean is one port in the LAG may hit line rate before the others are even using 50 percent of bandwidth.

*    1 52    WS-C2960X-48LPS-L         15.2(2)E6
sh platform pm platform-block
interface gid gpn lpn asic
--------------------------
Gi1/0/1   1   1   1   0   
Gi1/0/2   2   2   2   0   
Gi1/0/3   3   3   3   0   
Gi1/0/4   4   4   4   0   
Gi1/0/5   5   5   5   0   
Gi1/0/6   6   6   6   0   
Gi1/0/7   7   7   7   0   
Gi1/0/8   8   8   8   0   
Gi1/0/9   9   9   9   0   
Gi1/0/10  10  10  10  0   
Gi1/0/11  11  11  11  0   
Gi1/0/12  12  12  12  0   
Gi1/0/13  13  13  13  0   
Gi1/0/14  14  14  14  0   
Gi1/0/15  15  15  15  0   
Gi1/0/16  16  16  16  0   
Gi1/0/17  17  17  17  0   
Gi1/0/18  18  18  18  0   
Gi1/0/19  19  19  19  0   
Gi1/0/20  20  20  20  0   
Gi1/0/21  21  21  21  0   
Gi1/0/22  22  22  22  0   
Gi1/0/23  23  23  23  0   
Gi1/0/24  24  24  24  0   
Gi1/0/25  25  25  25  1   
Gi1/0/26  26  26  26  1   
Gi1/0/27  27  27  27  1   
Gi1/0/28  28  28  28  1   
Gi1/0/29  29  29  29  1   
Gi1/0/30  30  30  30  1   
Gi1/0/31  31  31  31  1   
Gi1/0/32  32  32  32  1   
Gi1/0/33  33  33  33  1   
Gi1/0/34  34  34  34  1   
Gi1/0/35  35  35  35  1   
Gi1/0/36  36  36  36  1   
Gi1/0/37  37  37  37  1   
Gi1/0/38  38  38  38  1   
Gi1/0/39  39  39  39  1   
Gi1/0/40  40  40  40  1   
Gi1/0/41  41  41  41  1   
Gi1/0/42  42  42  42  1   
Gi1/0/43  43  43  43  1   
Gi1/0/44  44  44  44  1   
Gi1/0/45  45  464 45  1   
Gi1/0/46  46  465 46  1   
Gi1/0/47  47  457 47  1   
Gi1/0/48  48  456 48  1   
Gi1/0/49  49  49  49  0   
Gi1/0/50  50  50  50  0   
Gi1/0/51  51  51  51  1   
Gi1/0/52  52  52  52  1   

-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Bryan Holloway
Sent: Thursday, December 14, 2017 7:55 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Cisco 3750G backplane throughput

This message originates from outside of your organisation.

Hello community,

I'm curious if someone is in the know or can point me to a document that describes how the backplane is carved up on a 3750G. I.e., ports per ASIC, etc., if applicable. I've dug around the Cisco docs to no avail.

I'm particularly interested to know how the four-port SFP section is handled on, for example, a WS-C3750G-24TS. Does it have its own ASIC for all four SFP ports? Or is that also carved up amongst other ports? If one were to LAG all four SFP ports together, should one expect to be able to reach a full 4 Gbps (assuming no taxation from other switch ports?)

We're running into an odd issue where we're unable to achieve more than
2 Gbps of bandwidth, but I have a hard time believing this is a switch limitation.

Any input would be most appreciated, thanks!

			- bryan
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