Join Chris Bryant for an in-depth discussion in this video Unidirectional link detection (UDLD), part of CCNP Troubleshooting (300-135) Cert Prep.
- [Narrator] In the last minute or so of the previous video,…we saw an example that gave us another reason…BPDUs may not arrive at their destination.…It wasn't a downed cable, it was unidirectional link.…Where A can send to B, B can't send to A,…or as I've got on the board here, one can send to two,…but two can't send a BPDU back to one.…UDLD helps us detect this. The basic operation is simple,…and it's going to sound pretty familiar.…A UDLD enabled port sends a UDLD frame across the link…every 15 seconds by default. If something comes back,…we have a bidirectional link and all is well.…
If nothing comes back, we have a unidirectional link…and not all is well.…That sent UDLD message,…it sounds like a radio station,…lets the recipient know what device sent the message,…and what port it was on. It's going to have a device ID…and port ID inside of it. The recipient sends it right back,…on the same port that received the message.…It's a frame and an echo. It's a kind of ping.…It's really a keep alive more than anything else,…
- Port security fundamentals
- EtherChannel negotiation protocols
- Advanced switching options
- NBMA configuration and troubleshooting
- Spotting and fixing authentication type mismatches
- K-values and passive interfaces
- Route redistribution
- NTP authentication
- Border Gateway Protocol (BGP)
- VPNs and VRF-lite
Skill Level Intermediate
1. CCNP TSHOOT 300-135: Switching and EC Fundamentals
2. CCNP TSHOOT 300-135: Advanced Switching Options
3. CCNP TSHOOT 300-135: Analyzing And Troubleshooting OSPF
4. CCNP TSHOOT 300-135: Enhanced Interior Gateway Routing Protocol (EIGRP)
5. CCNP TSHOOT 300-115: Route Redistribution
To autoredistribute (or not)8m 34s
6. TSHOOT 300-115: The Hot Standby Routing Protocol
7. CCNP TSHOOT 300-115: Access Control Lists (ACLs)
8. CCNP TSHOOT 300-115: Border Gateway Protocol (BGP)
9. TSHOOT 300-135: VPNs and VRF-lite
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