From: Kelly, Russell G (Russell_Kelly@eu1.bp.com)
Date: Sun Nov 16 2003 - 08:59:55 GMT-3
Non-silent is important if the etherchannel is between two devices sending pagp traffic btwn each other. Silent is configured if connecting to a device that is not pagp capable. Essentially operating in silent mode effectively disables the advantages pagp gives you. In fact as far as the mode goes, I seem to remember that if ether-channel mode is set to 'on' if one link goes down the whole etherchannel goes down. Therefore desirable (non-silent) will enable the etherchannel to 'manage' a single link failure, remain up and load balance across the remaining links as it understands pagp packets recived from the adjoining device. Silent mode doesn't stop the phys port from joining the etherchannel and using the int for transmission. I agree, info on this is a little sketchy though. Though I would imagine that in an etherchannel btwn pagp enabled devices non-silent is 'more-correct'. See below for pagp info and brief summ on non-silent mode (note in our HA network we always !
configure non-silent mode on ether-channels btwn devices)
Understanding the Port Aggregation Protocol
===========================================
The Port Aggregation Protocol (PAgP) facilitates the automatic creation of EtherChannels by exchanging packets between Ethernet interfaces. By using PAgP, the switch learns the identity of partners capable of supporting PAgP and learns the capabilities of each interface. It then dynamically groups similarly configured interfaces into a single logical link (channel or aggregate port); these interfaces are grouped based on hardware, administrative, and port parameter constraints. For example, PAgP groups the interfaces with the same speed, duplex mode, native VLAN, VLAN range, and trunking status and type. After grouping the links into an EtherChannel, PAgP adds the group to the spanning tree as a single switch port.
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.
-----Original Message-----
From: Adminl@kuix.com [mailto:Adminl@kuix.com]
Sent: 16 November 2003 10:47
To: ccielab@groupstudy.com
Subject: channel-group with mode desirable non-silent
Dears...
I have 2 cats 3550 with 2 links..with following configuration
Sw1&SW2
interface FastEthernet0/23
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
channel-group 1 mode desirable non-silent
!
interface FastEthernet0/24
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
channel-group 1 mode desirable non-silent
Is non-silent here is important or can configure it without this keyword,,Or both is right???
Sw1&SW2
interface FastEthernet0/23
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
channel-group 1 mode desirable
!
interface FastEthernet0/24
switchport trunk encapsulation dot1q
switchport mode trunk
no ip address
channel-group 1 mode desirable
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