Name: Cisco Catalyst 2960 Series
Brand: Cisco
Rating: 5 (1 reviews)

To Next Page

To Previous Page

EtherChannel Guard

You can use EtherChannel guard to detect an EtherChannel misconfiguration between the switch and a

connected device. A misconfiguration can occur if the switch interfaces are configured in an EtherChannel,

but the interfaces on the other device are not. A misconfiguration can also occur if the channel parameters are

not the same at both ends of the EtherChannel.

If the switch detects a misconfiguration on the other device, EtherChannel guard places the switch interfaces

in the error-disabled state, and displays an error message.

Related Topics

Enabling EtherChannel Guard , on page 310

Root Guard

The Layer 2 network of a service provider (SP) can include many connections to switches that are not owned

by the SP. In such a topology, the spanning tree can reconfigure itself and select a customer switch as the root

switch. You can avoid this situation by enabling root guard on SP switch interfaces that connect to switches

in your customer’s network. If spanning-tree calculations cause an interface in the customer network to be

selected as the root port, root guard then places the interface in the root-inconsistent (blocked) state to prevent

the customer’s switch from becoming the root switch or being in the path to the root.

Figure 28: Root Guard in a Service-Provider Network

If a switch outside the SP network becomes the root switch, the interface is blocked (root-inconsistent state),

and spanning tree selects a new root switch. The customer’s switch does not become the root switch and is

not in the path to the root.

If the switch is operating in multiple spanning-tree (MST) mode, root guard forces the interface to be a

designated port. If a boundary port is blocked in an internal spanning-tree (IST) instance because of root

guard, the interface also is blocked in all MST instances. A boundary port is an interface that connects to a

Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)

297

Information About Optional Spanning-Tree Features

Cisco Catalyst 2960 Series User Manual

Other manuals for Cisco Catalyst 2960 Series