8/9/10

ASIC to Port Mappings

If you've ever tried to plan your port over-subscription, work with PVLANs, design a QoS policy, or been involved with advanced troubleshooting, you've probably wanted to know the port to ASIC assignments.  This page is designed to help you find that mapping for the major Catalyst platforms.

In the 6500 platform, it's easily displayed with "show interface capabilities".  Below is the sample output from the command.  The portion we're interested in is labeled "Ports-in-ASIC".

6500-1#show interface capabilities module 2
GigabitEthernet2/1
  Model:                 WS-X6724-SFP
  Type:                  1000BaseSX
  Speed:                 1000
  Duplex:                full
  Trunk encap. type:     802.1Q,ISL
  Trunk mode:            on,off,desirable,nonegotiate
  Channel:               yes
  Broadcast suppression: percentage(0-100)
  Flowcontrol:           rx-(off,on,desired),tx-(off,on,desired)
  Membership:            static
  Fast Start:            yes
  QOS scheduling:        rx-(1q8t), tx-(1p3q8t)
  QOS queueing mode:     rx-(cos), tx-(cos)
  CoS rewrite:           yes
  ToS rewrite:           yes
  Inline power:          no
  Inline power policing: no
  SPAN:                  source/destination
  UDLD                   yes
  Link Debounce:         yes
  Link Debounce Time:    yes
  Ports-in-ASIC (Sub-port ASIC) : 1-24 (1-12)
  Remote switch uplink:  no
  Dot1x:                 no
  Port-Security:         yes

On the smaller platforms, the ASIC information is not included in the interface capabilities.  Luckily, it's still obtainable, but from different commands.

On the 4500 platform, you'll use "show platform mapping ports interface":

4500-1#show platform mapping ports interface gigabitEthernet 3/1
Interface  Gigaport  Phyport  Aggport    PimPhyport
Gi3/1      23        185      1          0

You're interested in the Gigaport number.  Unfortunately, I was unable to find a command to list this data for all of the ports on a card, so you'll have to re-issue it for all of the ports.

On the smaller catalyst platforms, like the 2960, 3560, 3750, and 3120X (HP Blade Frame Switches), you'll find it under "sh platform pm if-numbers":

3120X-1#sh platform pm if-numbers

interface gid  gpn  lpn  port slot unit slun port-type lpn-idb gpn-idb
----------------------------------------------------------------------
Gi1/0/1   1    1    1    1/6  1    1    1    local     Yes     Yes
Gi1/0/2   2    2    2    1/8  1    2    2    local     Yes     Yes
Gi1/0/3   3    3    3    1/10 1    3    3    local     Yes     Yes
Gi1/0/4   4    4    4    1/12 1    4    4    local     Yes     Yes
Gi1/0/5   5    5    5    1/16 1    5    5    local     Yes     Yes
Gi1/0/6   6    6    6    1/18 1    6    6    local     Yes     Yes
Gi1/0/7   7    7    7    1/20 1    7    7    local     Yes     Yes
Gi1/0/8   8    8    8    1/22 1    8    8    local     Yes     Yes
Gi1/0/9   9    9    9    1/7  1    9    9    local     Yes     Yes
Gi1/0/10  10   10   10   1/9  1    10   10   local     Yes     Yes
Gi1/0/11  11   11   11   1/11 1    11   11   local     Yes     Yes
Gi1/0/12  12   12   12   1/13 1    12   12   local     Yes     Yes
Gi1/0/13  13   13   13   1/17 1    13   13   local     Yes     Yes
Gi1/0/14  14   14   14   1/19 1    14   14   local     Yes     Yes
Gi1/0/15  15   15   15   1/21 1    15   15   local     Yes     Yes
Gi1/0/16  16   16   16   1/23 1    16   16   local     Yes     Yes
Gi1/0/17  17   17   17   1/4  1    17   17   local     Yes     Yes
Gi1/0/18  18   18   18   1/15 1    18   18   local     Yes     Yes
Gi1/0/19  19   19   19   0/6  1    19   19   local     Yes     Yes
Gi1/0/20  20   20   20   0/7  1    20   20   local     Yes     Yes
Gi1/0/21  21   21   21   0/21 1    21   21   local     Yes     Yes
Gi1/0/22  22   22   22   0/20 1    22   22   local     Yes     Yes
Gi1/0/23  23   23   23   1/1  1    23   23   local     Yes     Yes
Gi1/0/24  24   24   24   1/0  1    24   24   local     Yes     Yes
Gi1/0/25  25   25   25   1/27 1    25   25   local     Yes     Yes
Gi1/0/26  26   26   26   1/26 1    26   26   local     Yes     Yes
Te1/0/1   27   27   27   0/0  1    1    27   local     Yes     Yes
Te1/0/2   28   28   28   0/14 1    2    28   local     Yes     Yes
St1       768  768  0    16/0  1    0    0    internal  Yes     Yes

Looking at Gi1/0/1, we're interested in the "port" column, it's 1/6.  This means it's on ASIC #1 using port #6.

On CCO, I've been unable to find any good architecture documents, for the smaller switches, that list the ASIC layout.  I figured this might be a good place to start a running list for the switches that I regularly deal with:
Model  Port ASIC
WS-C3750G-24TS Gi 1/0/1 - 3 1

Gi 1/0/5 - 8 2

Gi 1/0/9 - 12 0

Gi 1/0/13 - 16 3

Gi 1/0/17 - 20 6

Gi 1/0/21 - 22 4

Gi 1/0/23 - 24 5

Gi 1/0/25 - 26 4

Gi 1/0/27 - 28 5



WS-C3750E-48TD-S Gi 1/0/1 - 24 1

Gi 1/0/25 - 48 2

Gi 1/0/49 - 52 0

Te 1/0/1 - 2 0



WS-C3560-24PS-S Fa 0/1 - 24 0

Gi 0/1 - 2 0



WS-CBS3120X-S Gi 1/0/1 - 18 1

Gi 1/0/19 - 22 0

Gi 1/0/23 - 26 1

Te 1/0/1 - 2 0



WS-CBS3020-HPQ Gi 0/1 - 2 4

Gi 0/3 - 4 2

Gi 0/5 - 6 1

Gi 0/7 - 8 0

Gi 0/9 - 10 5

Gi 0/11 - 12 3

Gi 0/13 - 14 1

Gi 0/15 - 16 0

Gi 0/17 - 18 3

Gi 0/19 - 20 2

Gi 0/21 - 22 5

Gi 0/23 - 24 4



WS-C3560G-24TS Gi 0/1 - 4 1

Gi 0/5 - 8  0

Gi 0/9 - 12 3

Gi 0/13 - 16 2

Gi 0/17 - 20 6

Gi 0/21 - 24 5

Gi 0/25 - 28 4



WS-C3560E-12D-S Gi 0/1 - 4 0

Gi 0/5 - 8  1

Gi 0/9 - 12 2

Gi 0/13 - 16 3

Gi 0/17 - 20 4

Gi 0/21 - 24 5

Te 0/1 - 2 0

Te 0/3 - 4 1

Te 0/5 - 6 2

Te 0/7 - 8 3

Te 0/9 - 10 4

Te 0/11 - 12 5



WS-C2960-24TC-L Fa 0/1 - 24 0

Gi 0/1 - 2 0
In a future article, we'll walk though how to troubleshoot performance problems related to ASIC over-subscription and insufficient queue allocations.

[Added 9/12/2010]

The buffer allocations are not very well documented, and most of what I have is covered by NDA, but I did find one place that discusses it publicly: 

http://www.cisco.com/en/US/docs/solutions/Enterprise/Video/tpqoscampus.html

Catalyst 3560G/3750G and 3650-E/3750E 
[SNIP]
Additionally, these platforms provide (minimally) 750 KB of receive buffers and (up to) 2 MB of transmit buffers for each set of 4 ports. These buffers can be allocated, reserved, or dynamically borrowed from a common pool, on a port-port, per-queue basis, depending on the administrative configurations chosen.
Posted by James Ventre
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11 comments:

  1. Thanks for taking the time to write this excellent document. Helped me out!

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  2. This article is fantastic! I'm forwarding a link to it to my whole networking team! Thank you!

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  3. Nice !! Is there a command for a 3548 switch, specifically WS-3548-XL ? Thank You !!

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  4. There might be, but I don't have access to the older XL platforms.

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  5. I searched a lot, but didn't find any :(
    Also 3548 does not take 'sh interface summary' command, to look for i/p and o/p queue drops.

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  6. I know this will end up sounding dense, but under the 4500 chassis, the Gigaport number was 23. Can you explain how to translate that to an Asic #?

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    Replies

    1. What's important is which other ports share that ASIC (ie. they have the same Gigaport number), not necessarily whether it's ASIC #1, 2 or 3. Make sense?

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  7. Well done! Troubleshot an issue with ARP requests disappearing on a 2960G from 3 select servers. sh platform pm if-numbers helped me make it water tight.

    BTW, linked here by http://www.gossamer-threads.com/lists/engine?do=post_view_flat;post=137016;page=1;sb=post_latest_reply;so=ASC;mh=25;list=cisco

    -Charlie

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  8. For the 3500-XL family, see http://www.nasi.com/docs/pdfs/cisco3500xldatasheet.pdf. It looks like the 10/100 ports are attached to an octal Ethernet satellite.

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  9. Good work. 2014 and this is still relevant. It is a pity Cisco are so poor at providing information. We had to go through our top contacts to get snippets for a 3560x buffer allocation scheme, which looks inaccurate from lab tests we have performed.

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  10. That is so true 2014 and still relevant. This helped me out. Thanks!

    ReplyDelete

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