Transcript Routed Protocols

Chabot College
ELEC 99.05
Routed and Routing Protocols
CISCO NETWORKING ACADEMY
Routed vs Routing Protocols
CISCO NETWORKING ACADEMY
Routed Protocols
• Used by end systems to communicate
(a computer to another computer, etc.)
• Contain network-layer addresses of source
and destination computers.
• Examples:
• TCP/IP
• IPX/SPX
• AppleTalk
CISCO NETWORKING ACADEMY
Routing Protocols
• Used by intermediate systems to
communicate information about paths
(router to router).
• Contain routing information tables.
• Examples:
•
•
•
•
RIP
IGRP
EIGRP
OSPF
CISCO NETWORKING ACADEMY
2 Kinds of Routing Protocols
• IGPs, Interior Gateway Protocols: used
by routers inside an organization’s
network
• EGPs, Exterior Gateway Protocols: used
between different organization’s routers
CISCO NETWORKING ACADEMY
EGPs
• We won’t study EGPs in this class.
• There are two common EGPs:
– EGP: Exterior Gateway Protocol
– BGP: Border Gateway Protocol
• BGP is newer and the most common.
CISCO NETWORKING ACADEMY
IGPs
• We study four IGPs in class:
– RIP
– IGRP
– EIGRP
– OSPF
CISCO NETWORKING ACADEMY
RIP
• RIP, or Routing Information Protocol
– Very old protocol
– Uses only one measure, or metric, to
determine the desirability of a route: hop
count
– This type of metric is called distancevector
– Broadcasts routing information to
neighbors every 30 seconds by default
CISCO NETWORKING ACADEMY
Hop Count
• Hop count is the number of routers a
packet must past through to reach a
destination.
• RIP always chooses the path that has
the fewest hops.
(not always the fastest path)
• RIP can only support routes with a hop
count of less than 16.
(16 is unreachable).
CISCO NETWORKING ACADEMY
IGRP
• IGRP, or Interior Gateway Routing
Protocol
– Cisco-proprietary
– Uses multiple measures, or metrics, to
determine best path, including bandwidth
– Distance-vector metric
– Preferred over RIP
CISCO NETWORKING ACADEMY
OSPF
• Open Shortest Path First
– Non-proprietary
– Uses multiple metrics
– Updates directly to all routers, not just to
neighbors
– Link state metric
CISCO NETWORKING ACADEMY
EIGRP
• EIGRP, or Enhanced Interior Gateway
Protocol
– Cisco-Proprietary
– Uses multiple metrics
– Combines features of distance vector and
link state routing protocols (a cross
between IGRP and OSPF)
CISCO NETWORKING ACADEMY
Static vs. Dynamic Routes
• Static Route
– Configured manually into the router.
– Useful for stub networks
• Dynamic Route
– Learned automatically and adjusts for
topology or traffic changes
– Useful when multiple paths are available
CISCO NETWORKING ACADEMY
Static vs. Dynamic Routes
• Which are stub networks?
• Which offer multiple paths?
• Where would we use each type of
route?
CISCO NETWORKING ACADEMY
Convergence
• Link State routing protocols converge
faster than distance vector routing
protocols.
CISCO NETWORKING ACADEMY
End-to-End Routing
CISCO NETWORKING ACADEMY
Multiprotocol Routing
CISCO NETWORKING ACADEMY