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NonBlocking connections to WS-X6748-GE-TX

nsysblh
Level 1
Level 1

I understand that the WS-X6748-GE-TX connects to the switch fabric via 2 20gbps connections. Therefore, the 48 port card isn't non-blocking when fully deployed. Apparently, because of the internal tagging, it appears that only 38 ports can be simultaneously active at 1000 and the card remain totally non-blocking. From one of the install docs, it says the card is really divided into 4 port groups, not 2.

I haven't found any definitive answers, so I thought I'd ask here.

What are the port number ranges in each section of the card (and are there 2 sections or 4), and how many 1000 connections can be made to each to leave the card non-blocking? Can the rest of the ports in that section run at 100 and the card still remain non-blocking?

1 Accepted Solution

Accepted Solutions

Prashanth Krishnappa
Cisco Employee
Cisco Employee

If you want to design for the worst-case scenario of all 64-byte packets and need all non blocking ports, then 32 ports is what you can use in each WS-X6748-GE-TX. You would need to use 16 out of each group of 24 ports (1-24 and 25-48).

You cannot use any more if you are sending sustained 1 Gig traffic on all 32 ports

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3 Replies 3

Prashanth Krishnappa
Cisco Employee
Cisco Employee

If you want to design for the worst-case scenario of all 64-byte packets and need all non blocking ports, then 32 ports is what you can use in each WS-X6748-GE-TX. You would need to use 16 out of each group of 24 ports (1-24 and 25-48).

You cannot use any more if you are sending sustained 1 Gig traffic on all 32 ports

Could the other 8 ports in each half of the card be used for 100 and still remain non-blocking in the worst case?

If there is sustained 1 gig traffic on 16 ports in the bank of 24, I would expect to see some contention for access to backplane and see some drops.