MPLS Guide Label Distribution Protocol
3HE 18686 AAAB TQZZA © 2022 Nokia.
Use subject to Terms available at: www.nokia.com
377
5.1.7 LDP FEC Statistics
LDP FEC statistics allow operators to monitor traffic being forwarded between any
two PE routers and for all services using an LDP SDP. LDP FEC statistics are
available for the egress data path at the ingress LER and LSR. Because an ingress
LER is also potentially an LSR for an LDP FEC, combined egress data path statistics
are provided whenever applicable. For more information, see RSVP LSP and LDP
FEC Statistics.
5.1.8 Multi-area and Multi-instance Extensions to LDP
When a network has two or more IGP areas, or instances, inter-area LSPs are
required for MPLS connectivity between the PE devices that are located in the
distinct IGP areas. In order to extend LDP across multiple areas of an IGP instance
or across multiple IGP instances, the current standard LDP implementation based on
RFC 3036, LDP Specification, requires that all /32 prefixes of PEs be leaked between
the areas or instances. IGP route leaking is the distribution of the PE loopback
addresses across area boundaries. An exact match of the prefix in the routing table
(RIB) is required to install the prefix binding in the FIB and set up the LSP.
This behavior is the default behavior for the 7705 SAR when it is configured as an
Area Border Router (ABR). However, exact prefix matching causes performance
issues for the convergence of IGP on routers deployed in networks where the
number of PE nodes scales to thousands of nodes. Exact prefix matching requires
the RIB and FIB to contain the IP addresses maintained by every LSR in the domain
and requires redistribution of a large number of addresses by the ABRs. Security is
a potential issue as well, as host routes leaked between areas can be used in DoS
and DDoS attacks and spoofing attacks.
Note: In order for the 7705 SAR to consider a received label to be active, there must be an
exact match to the FEC advertised together with the label found in the routing table, or a
longest prefix match (if the aggregate-prefix-match option is enabled; see Multi-area and
Multi-instance Extensions to LDP). This can be achieved by configuring a static route
pointing to the prefix encoded in the FEC.
To Next Page
Loading...
Need help?
General
