Content deleted Content added
No edit summary |
No edit summary |
||
Line 2:
'''Unidirectional Link Detection''' ('''UDLD''') is a [[data link layer]] protocol from [[Cisco Systems]] to monitor the physical configuration of the cables and detect unidirectional links. UDLD complements the [[Spanning Tree Protocol]] which is used to eliminate [[switching loop]]s.
:* Unidirectional Link Detection (UDLD) is one of two major features (UDLD and loop guard) in Cisco Switches to prevent Layer 2 loops.
:* Spanning-Tree Protocol (STP) resolves redundant physical topology into a loop-free, tree-like forwarding topology via blocking one or more ports.
: However, Unidirectional Link failure can cause " traffic blackholing" and loop in the Switch topology.
:* In order to detect the unidirectional links before the forwarding loop is created, UDLD works by exchanging protocol packets between the neighboring devices.
:* In order for UDLD to work, both switch devices on the link must support UDLD and have it enabled on respective ports.▼
▲: In order for UDLD to work, both switch devices on the link must support UDLD and have it enabled on respective ports.
==Description==
| |||