Understanding SRLB (Segment Routing Local Block)
# What is SRLB?
* SRLB (Segment Routing Local Block) is a range of local MPLS labels used by Segment Routing (SR-MPLS).
* These labels are only relevant to the local router and are not advertised to other routers.
# Key SR-MPLS Label Blocks:# SRGB (Segment Routing Global Block) - Globally significant labels shared among routers.# SRLB (Segment Routing Local Block) - Locally significant labels, not shared.
Why is the Answer TRUE?
# SRLB labels are only locally defined and are NOT distributed via IGP (OSPF or IS-IS).# They are used for local forwarding decisions within an SR-enabled router.# Only SRGB labels are advertised to ensure consistent global label assignment.
Real-World Application:
* Traffic Engineering (TE): Uses SRLB for custom local path optimizations.
* Segment Routing Networks: Ensures scalable MPLS forwarding without requiring full LDP signaling.
# Reference: Huawei HCIE-Datacom Guide - Segment Routing Label Blocks (SRGB & SRLB)