What are the two most common distance-vector routing protocols?
- RIP and BGP
- IS-IS and BGP
- BGP and IGRP
- RIP and OSPF
EXPLANATION
Distance
vector routing is so named because it involves two factors: the
distance, or metric, of a destination, and the vector, or direction to
take to get there. Routing information is only exchanged between
directly connected neighbors. This means a router knows from which
neighbor a route was learned, but it does not know where that neighbor
learned the route; a router can't see beyond its own neighbors. This
aspect of distance vector routing is sometimes referred to as "routing
by rumor." Measures like split horizon and poison reverse are employed
to avoid routing loops.
Link-state routing, in contrast, requires
that all routers know about the paths reachable by all other routers in
the network. Link-state information is flooded throughout the
link-state domain (an area in OSPF or IS-IS) to ensure all routers
posses a synchronized copy of the area's link-state database. From this
common database, each router constructs its own relative shortest-path
tree, with itself as the root, for all known routes.
http://packetlife.net/blog/2008/oct/2/distance-vector-versus-link-state/
Routing
protocols can be classified into different groups according to their
characteristics. Specifically, routing protocols can be classified by
their:
Purpose: Interior Gateway Protocol (IGP) or Exterior Gateway Protocol (EGP)
Operation: Distance vector protocol, link-state protocol, or path-vector protocol
Behavior: Classful (legacy) or classless protocol
For example, IPv4 routing protocols are classified as follows:
RIPv1 (legacy): IGP, distance vector, classful protocol
IGRP (legacy): IGP, distance vector, classful protocol developed by Cisco (deprecated from 12.2 IOS and later)
RIPv2: IGP, distance vector, classless protocol
EIGRP: IGP, distance vector, classless protocol developed by Cisco
OSPF: IGP, link-state, classless protocol
IS-IS: IGP, link-state, classless protocol
BGP: EGP, path-vector, classless protocol
The classful routing protocols, RIPv1 and IGRP, are legacy protocols and are only used in older networks. These routing protocols have evolved into the classless routing protocols, RIPv2 and EIGRP, respectively. Link-state routing protocols are classless by nature.
Purpose: Interior Gateway Protocol (IGP) or Exterior Gateway Protocol (EGP)
Operation: Distance vector protocol, link-state protocol, or path-vector protocol
Behavior: Classful (legacy) or classless protocol
For example, IPv4 routing protocols are classified as follows:
RIPv1 (legacy): IGP, distance vector, classful protocol
IGRP (legacy): IGP, distance vector, classful protocol developed by Cisco (deprecated from 12.2 IOS and later)
RIPv2: IGP, distance vector, classless protocol
EIGRP: IGP, distance vector, classless protocol developed by Cisco
OSPF: IGP, link-state, classless protocol
IS-IS: IGP, link-state, classless protocol
BGP: EGP, path-vector, classless protocol
The classful routing protocols, RIPv1 and IGRP, are legacy protocols and are only used in older networks. These routing protocols have evolved into the classless routing protocols, RIPv2 and EIGRP, respectively. Link-state routing protocols are classless by nature.
0 comments:
Post a Comment