PAgP silent mode

[Ahmet Mustafa Mungan]

Hello everyone,

I have read lots of different documents about silent mode in PAgP. However I still did net get the purpose of it.

This is from Cisco:

Use the silent mode when the switch is connected to a device that is not PAgP-capable and seldom, if ever, sends 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 port to a channel group, and to use the port for transmission.

1) According to that paragraph, I can't see any difference between "on mode" and "desirable/auto with silent mode". What is the difference between them?

2) When silent mode enabled, I see no difference between desirable and auto mode. Because according to the paragraph, etherchannel will be operational and it is independent if we take any PAgP packets or not. So, what is the difference between desirable and auto mode when silent keyword used?

Kind Regards,

Ahmet

[Georg Pauwen]

Hello,

'on' means that you effectively eliminate PAgP. In 'on' mode, no PAgP packets are exchanged at all, and the channel will form no matter what. This is typically used for non-Cisco devices.

If you want to use PAgP, and if one side is not PAgP capable, you use the 'silent' setting on that side.

So basically, 'desirable' and 'auto' are used between Cisco devices, and 'silent' for non-PAgP capable (usually non-Cisco) devices.

[Ahmet Mustafa Mungan]

Hi gpauwen,

I do know that "on mode" is different than PAgP. I wanted to mean that "PAgP with silent mode" and "on mode" seems the same from the operational point of view. Because based on your and Cisco's explanation, silent mode is used when the other side is not capable for PAgP. For my understanding, that means unconditional channeling of the links without using any channeling protocol. And that is exactly the same with what "on mode" does.

Kind Regards,

Ahmet