Silent Mode - Cisco Catalyst 2960 series Configuration Manual

Information About EtherChannels
Default EtherChannel Configuration, on page 337
Layer 2 EtherChannel Configuration Guidelines, on page 340
Configuring the Physical Interfaces
EtherChannel Configuration Guidelines, on page 338
Default EtherChannel Configuration, on page 337
Layer 2 EtherChannel Configuration Guidelines, on page 340

Silent Mode

If your switch is connected to a partner that is PAgP-capable, you can configure the switch port for nonsilent
operation by using the non-silent keyword. If you do not specify non-silent with the auto or desirable mode,
silent mode is assumed.
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.
Related Topics
Configuring Layer 2 EtherChannels , on page 342
EtherChannel Configuration Guidelines, on page 338
Default EtherChannel Configuration, on page 337
Layer 2 EtherChannel Configuration Guidelines, on page 340
Creating Port-Channel Logical Interfaces
EtherChannel Configuration Guidelines, on page 338
Default EtherChannel Configuration, on page 337
Layer 2 EtherChannel Configuration Guidelines, on page 340
Configuring the Physical Interfaces
EtherChannel Configuration Guidelines, on page 338
Default EtherChannel Configuration, on page 337
Layer 2 EtherChannel Configuration Guidelines, on page 340
PAgP Learn Method and Priority
Network devices are classified as PAgP physical learners or aggregate-port learners. A device is a physical
learner if it learns addresses by physical ports and directs transmissions based on that knowledge. A device
is an aggregate-port learner if it learns addresses by aggregate (logical) ports. The learn method must be
configured the same at both ends of the link.
When a device and its partner are both aggregate-port learners, they learn the address on the logical port-channel.
The device sends packets to the source by using any of the ports in the EtherChannel. With aggregate-port
learning, it is not important on which physical port the packet arrives.
PAgP cannot automatically detect when the partner device is a physical learner and when the local device is
an aggregate-port learner. Therefore, you must manually set the learning method on the local device to learn
addresses by physical ports. You also must set the load-distribution method to source-based distribution, so
that any given source MAC address is always sent on the same physical port.
You also can configure a single port within the group for all transmissions and use other ports for hot-standby.
The unused ports in the group can be swapped into operation in just a few seconds if the selected single port
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
330