LDP
LDP (Label Distribution Protocol) distributes MPLS labels. Two devices with an established LDP session are LDP peers and exchange labels bidirectionally. LDP builds and maintains the LSP databases used to forward traffic in MPLS networks.
LDP discovery uses UDP port 646, while the session uses TCP port 646. During discovery, Hello packets are sent to multicast address 224.0.0.2.
Basic LDP Settings
| Field | Description | Default |
|---|---|---|
| Enable LDP | Enable or disable LDP | Off |
| LSR ID | LSR identifier, for example 10.10.10.2 | 10.10.10.10 |
| Hostname | Hostname | bngblaster |
| IPv4 transport address | IPv4 transport-interface address | Same as LSR ID |
| IPv6 transport address | IPv6 transport-interface address | — |
| No IPv4 transport | Disable IPv4 LDP Hello messages | Off |
| Prefer IPv4 transport | Prefer IPv4 transport when IPv6 is available | Off |
LDP Timers
| Field | Description | Default |
|---|---|---|
| Keepalive time (s) | LDP session keepalive timeout, in seconds | 0 |
| Hold time (s) | LDP Hello hold time, in seconds | 0 |
| Teardown time (s) | Session teardown time, in seconds | 0 |
Prefix Source (from IGP)
LDP can automatically obtain prefixes from an IGP (Interior Gateway Protocol) to build MPLS LSPs.
| Field | Description | Value |
|---|---|---|
| Enable prefix source | Obtain prefixes from the IGP | On |
| Protocol | Source protocol: ISIS or OSPF | ISIS |
| Mode | Prefix selection: loopbacks (loopback addresses only) or all | loopbacks |
| Label base | Base label assigned to prefixes | 16000 |