06-30-2010 03:43 AM - edited 03-06-2019 11:50 AM
Hi Experts,
I am using 6509 Switch installed with WS-X6748-SFP module. I used the command "show interface gigabitethernet 1/1 capablities". I am seeing a lot of stuffs in the output. One thing which interested me is "Ports-in-ASIC (Sub-port ASIC)" information. Find the attached command output file.
Ports-in-ASIC (Sub-port ASIC) : 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47 (1,3,5,7,9,11,13,15,17,19,21,23)
Roughly i understood that One ASIC Port is shared with multiple Physical Ethernet ports.
I request your help to understand it more and provide me how it is oversubscribed. I checked in various documents, I am missing to get a good one
thnks in advance
Sairam
07-02-2010 12:44 AM
Hi Friends,
I hope this query is not answered may be kept unnoticed.
I appreciate your help in clarifying this
regards,
sairam
07-02-2010 01:36 AM
I think this explains it very well
"On switches a lot of port hardware is based on asics which control 4-8 ports on a slot . Each of the asics has a certain amount of bandwidth to the backplane of the switch . If a asic has a 4 gig backplane bandwidth but there 8 1 gig ports on that asic then those group of ports are oversubscribed for those given ports . This is only an issue if you get more than 4 of those connections running a full gig and is what cisco bets on when designing their switches this way ." . In your case you should try to see (or maybe some expert can give us this info) whats the bandwith of the connection to the backplane in that module to see how much oversubscrition there is
07-02-2010 04:22 AM
Hello,
The WS-X6748-SFP module has 3 levels of ASICs:
- Bus and Fabric ASICs : JANUS (x2) and SSA (x2)
- Port ASICs: ROHINI (x4)
Each ROHINI ASIC manages 12 GE ports and the recommended design oversubscription when this module is used on a Data Center is 1:2:1.
Hope this helps.
10-28-2010 11:42 AM
Hi Jorge,
What do you mean by 1:2:1?
Thanks,
10-28-2010 04:01 PM
Hi,
Actually it was a typo...I meant 1.2:1 --> 48 Gbps ports with 20 Gbps connection to the fabric (if you use a SUP720).
Cheers.
10-28-2010 04:10 PM
jorge.calvo wrote:
Hi,
Actually it was a typo...I meant 1.2:1 --> 48 Gbps ports with 20 Gbps connection to the fabric (if you use a SUP720).
Cheers.
Jorge
Sorry, did you mean 24Gbps ports with 20Gbps connection to fabric which is 1.2:1 ? as that module has 2 x 20Gbps conection to switch fabric.
Jon
10-28-2010 09:19 PM
jon.marshall wrote:
jorge.calvo wrote:
Hi,
Actually it was a typo...I meant 1.2:1 --> 48 Gbps ports with 20 Gbps connection to the fabric (if you use a SUP720).
Cheers.
Jorge
Sorry, did you mean 24Gbps ports with 20Gbps connection to fabric which is 1.2:1 ? as that module has 2 x 20Gbps conection to switch fabric.
Jon
It is indeed 24 ports to a 20-Gig channel.
Atif
10-29-2010 03:27 AM
Yes Jon,
It can be expressed as 24 x 1Gbps ports pors per 1 x 20Gbps Junos ASIC --> 1.2:1
Or
48 x 1Gpbs ports pero 1 x 20Gbps Junos ASIC --> 2.4:1 and having 2 Junos --> 1.2:1
Sorry for not being clear enough.
Cheers
10-29-2010 06:45 AM
Thanks much all...
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