DC-LDP
Data Connection is the leading supplier of MPLS software,
including LDP and its VPN extensions
Label Distribution Protocol (LDP) is often used to establish MPLS LSPs when traffic engineering is not required. It establishes LSPs that follow the existing IP routing, and is particularly well suited for establishing a full mesh of LSPs between all of the routers on the network.
LDP can operate in many modes to suit different requirements, however the most common usage is unsolicited mode, which sets up a full mesh of tunnels between routers.
- In solicited mode, the
ingress router sends an LDP label request to the next hop router, as determined
from its IP routing table. This request is forwarded on through the network
hop-by-hop by each router. Once the request reaches the egress router,
a return message is generated. This message confirms the LSP and tells
each router the label mapping to use on each link for that LSP.
- In unsolicited mode, the
egress routers broadcast label mappings for each external link to all
of their neighbors. These broadcasts are fanned across every link through
the network until they reach the ingress routers. Across each hop, they
inform the upstream router of the label mapping to use for each external
link, and by flooding the network they establish LSPs between all of the
external links.
The main advantage of LDP over RSVP is the ease of setting up a full mesh of tunnels using unsolicited mode, so it is most often used in this mode to set up the underlying mesh of tunnels needed by MPLS-enabled VPNs.
Data Connection's MPLS software, DC-MPLS, fully supports LDP in both solicited and unsolicited modes. For more information on DC-MPLS, see the link below.
Related links:
For more information about Data Connection's MPLS products and expertise contact dcmpls@dataconnection.com.