Segment Routing divides a network path into several segments which may include Nodes and links. And assigns a segment ID (SID) to each segment and forwarding node. A prefix segment identifier (SID) usually identifies a segment routing tunnel destination which is the loopback ip address of the destination node. An Adjacency Segment Identifier (adj-SID) is …
Segment Routing Flexible Algorithm (Flex-Algo) will provide easy way of calculating different paths with different type of constraints. It will allow us to define our own algorithm. This new algorithm can still be minimizing IGP metric but it can also be minimizing TE metric, minimizing delay metric (new metric definition added to IGP), avoiding some links or …
In the IGP based IP networks we have one simple algorithm and it calculates the shortest path to the destination according to planned IGP metric.IGP metric is the only constraint we can assign to the links. We have more with MPLS TE implementations like TE Metric, link admin group, bw etc. The problem with TE, …
TI-LFA also takes into account is SRLG exist in the network. Shared Risk Link Group (SRLG) is a set of links at the same risk of faults. If a link in an SRLG fails, other links also fail. In this case, if the other link in the SRLG functions as FRR backup to protect the failed …
TI-LFA can add one or more segment when switching traffic to backup and loop free alternate path. According to below topology let’s assume we want to protect not only the link between Node-A and Node-B but we also want to protect Node-B. Without TI-LFA, we can’t protect Node-B. According to formula it seems it isn’t possible …
Before Segment Routing was introduced, IP FRR and Loop-Free Alternates (LFAs) were not widely deployed. In these implementations the level of coverage depended on the network topology. When SR combined with FRR techniques, Fast Reroute can deliver 100% network coverage regardless of the topology. That is called TI-LFA (Topology Independent – Loop Free Alternate) Here …
IGP Adjacency Segment Identifier (Adj-SID) is a local label allocated from SRLB. It is attached to a unidirectional adjacency or a set of unidirectional adjacencies. Segment Routing Adj-SIDs usually represent a link (peering) and have a local significance. Of course It is used with Prefix-SID of local node. Locally significant means that the remote nodes …