Information Protocol (RIP)
RIP is a distance vector routing
protocol used for routing within an autonomous system (i.e.an IGP).
RIP uses the hop count as the metric.
RIP networks are limited in size to a maximum of 15
hops between any two networks. A network with a hop count of 16 indicates
an unreachable network.
RIP v1 is a classful protocol; RIP v2 is a classless
RIP is best suited for small private networks.
Interior Gateway Routing Protocol (EIGRP)
EIGRP is a hybrid routing protocol
developed by Cisco for routing within an AS.
EIGRP uses a composite number for the metric that
indicates bandwidth and delay for a link. The higher the bandwidth, the
lower the metric.
EIGRP is a classless protocol.
EIGRP is best suited for medium to large private
Open Shortest Path First (OSPF)
OSPF is a link state routing protocol used for routing within an AS.
OSPF uses a relative link cost for the metric.
OSPF is a classless protocol.
OSPF divides a large network into areas.
Each autonomous system requires an area 0 that
identifies the network backbone.
All areas are connected to area 0, either directly
or indirectly through another area.
Routes between areas must pass through area 0.
Internal routers share routes within an area;
area border routers share routes between areas; autonomous system
boundary routers share routes outside of the AS.
A router is the boundary between one area and another
OSPF is best suited for large private networks.
Intermediate System to Intermediate System (IS-IS)
IS-IS is a link state routing protocol used for routing within an AS.
IS-IS uses a relative link cost for the metric.
IS-IS is a classless protocol.
The original IS-IS protocol was not used for routing IP
packets; use Integrated IS-IS to include IP routing support.
IS-IS divides a large network into areas. There is no
area 0 requirement, and IS-IS provides greater flexibility than OSPF for
creating and connecting areas.
L1 routers share routes within an area; L2
routers share routes between areas; an L1/L2 router can share
routes with both L1 and L2 routers.
A network link is the boundary between one area and
IS-IS is best suited for large private networks,
supporting larger networks than OSPF. IS-IS is typically used within an ISP,
and easily supports IPv6 routing.
Border Gateway Protocol (BGP)
BGP is an advanced distance vector protocol (also called a path vector protocol). BGP is an exterior gateway protocol (EGP) used for routing between autonomous systems.