From: alsontra@hotmail.com
Date: Thu Mar 25 2004 - 01:05:45 GMT-3
Good question,
Let me start by saying that my research of the topic did not produce a
definite answer, but here's how I perceive it. Hopefully, one of the senior
members can shed some light on the subject.
Cisco states that non-silent mode is used to connect your switch to an
adjacent device that is not PAgP capable. They give the following example:
"non-silent -Keyword that is used with the auto or desirable mode when
traffic is expected from the other device.-
The silent mode is used when the switch is connected to a device that is not
PAgP-capable and seldom, if ever, transmits packets. An example of a silent
partner is a file server or a packet analyzer that is not generating
traffic. In this case, running PAgP on a physical port connected to a silent
partner prevents that switch port from ever becoming operational; however,
the silent setting allows PAgP to operate, to attach the interface to a
channel group, and to use the interface for transmission."
http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d84ca.html
In a nutshell, I take this to mean that port channels in either channel mode
auto or desirable will not be a forward traffic by default. Interfaces in
PAgP mode auto and desirable never obtain and operational forwarding state.
This is because interfaces in auto and desirable default to silent mode. To
allow a ports configured in PAgP mode desirable or auto to obtain a
forwarding state you must use the non-silent keyword. i.g.
SW1 fa0/1(channel mode auto)-------Server A <----server cannot access the
network
SW1fa0/2(channel mode desirable)---Server A<-----server cannot access the
network
SW1 fa0/1(channel mode auto-non_silent option)-------Server A <-----server
can access the network
SW1fa0/2(channel mode desirable-non_silent option)---Server A<-----server
can access the network
And that's my shot in the dark for today, does any know how this works?
Alsontra-
Dear all,
This topic may have been discussed, but I cannot get any answer from the
archive.
What is the different between non-silent and silent mode of PAgP?
I only know that if the neighbor is a PAgP capable device, you can use
either non-silent or silent mode, but silent mode is the default. If the
neighbor is a not PAgP capable, I must use silent mode. Since, silent mode
is the default and it works for both PAgP or non-PAgP neighbor, why we have
to use non-silent mode? What is the use of non-silent mode?
Best Regards,
William Chen
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