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congesting a back-to-back link on a switch

 
 
akmann7@gmail.com
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      07-07-2007
Hello experts,

Traffic source1 -------- Catalyst1 --------------Catalyst2
---------Traffic source 2

----------------------------------------Direction of Traffic
flow ----------------------->>>

Is there any way to congest the RX link on catalyst2 in above setup.
Basically I am trying to force the generation of flow control frames
between catalyst2 and catalyst1. Idea is if catalyst2 gets congested
on RX side, it will trigger flowcontrol frames to catalyst1 and then
catalyst1 should react to it.

I think the only way to congest will be to decrease the RX buffer
size on
catalyst2. Does anybody know how to achieve that on a RX port which
has following capablity....

GigabitEthernet1/1
Dot1x: yes
Model: WS-X6748-SFP
Type: 1000BaseT
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)
CoS rewrite: yes
ToS rewrite: yes
Inline power: no
SPAN: source/destination
UDLD yes
Link Debounce: yes
Link Debounce Time: no
Ports on ASIC: "bunch of ports"
Port-Security: yes

Any advide will be helpful. Thanks, Akmann

 
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stephen
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      07-07-2007
<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Hello experts,
>
> Traffic source1 -------- Catalyst1 --------------Catalyst2
> ---------Traffic source 2
>
> ----------------------------------------Direction of Traffic
> flow ----------------------->>>
>
> Is there any way to congest the RX link on catalyst2 in above setup.
> Basically I am trying to force the generation of flow control frames
> between catalyst2 and catalyst1. Idea is if catalyst2 gets congested
> on RX side, it will trigger flowcontrol frames to catalyst1 and then
> catalyst1 should react to it.


The 6724 card has 20 Gbps full duplex backplane link, and is split into 2 12
port sections fed by separate chips.

and if there is a DFC on this blade, then L3 forwarding happens locally, so
the backplane doesnt get touched for local traffic.
>
> I think the only way to congest will be to decrease the RX buffer
> size on
> catalyst2. Does anybody know how to achieve that on a RX port which
> has following capablity....


reducing the buffer pool would only help if there was more traffic coming in
that could get out again. Otherwise there is very little in the buffers
since packets go straight thru to the backplane.

basically if you want congestion you are going to have to load that and lots
of other ports with wire speed traffic - preferably using small packets to
increase the overhead in the backplane.

>
> GigabitEthernet1/1
> Dot1x: yes
> Model: WS-X6748-SFP
> Type: 1000BaseT
> 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)
> CoS rewrite: yes
> ToS rewrite: yes
> Inline power: no
> SPAN: source/destination
> UDLD yes
> Link Debounce: yes
> Link Debounce Time: no
> Ports on ASIC: "bunch of ports"
> Port-Security: yes
>
> Any advide will be helpful. Thanks, Akmann


you need to congest somewhere else unless you have a 15 to 20 port GigE
traffic generator.....
>

--
Regards

http://www.velocityreviews.com/forums/(E-Mail Removed) - replace xyz with ntl


 
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