Unit 1: Network Infrastructure
This will allow you to demonstrate your networking skills, knowledge, and abilities, with a focus on enterprise-level switching, routing, and multicast components that support cross-platform (inter)operability and integration with the most recent software-defined technologies.
UDLD, which stands for Unidirectional connection Detection, is a Layer 2 protocol that is exclusive to Cisco and is designed to assist in determining whether a connection fails to send or receive communication. It serves a role that is comparable to that of LoopGuard, but other than that, it is totally independent of Spanning Tree. For the most part, UDLD is a straightforward operation. UDLD Hellos are transmitted by a switch, and if it receives echoes of those Hellos back, it is able to determine that the link in question is an active two-way link. It comes to the realization that there must be a problem in the unidirectional link as soon as it stops getting the UDLD Hellos. It is important to note that UDLD functions at the physical port level, in contrast to STP LoopGuard, which operates at the logical port level (EtherChannel). Additionally, UDLD is able to function during linkup, whereas LoopGuard is unable. Enabling both UDLD and LoopGuard is something that is strongly suggested.
However, UDLD can also be beneficial on Ethernet connections that have dumb devices in the middle, such as media converters. Although its primary application is on fiber lines, one can also utilize it on Ethernet connections
At first, the advertisement timer runs for 15 seconds, and the hold time is 3 times the outgoing port’s message interval. You can set the message time to be anywhere from 1 to 90 seconds.When UDLD notices that a neighbor has been lost, it will send seven more advertisements, one every second. The link’s bidirectional state changes to “unknown” if no reply is received.
