RIP(Routing Information Protocol):
Distance Vector
Two versions: RIP1 and RIP2
RIP1 and IGRP include a feature called
auto summary that cannot be disabled.Auto summary is a feature of the
IOS that helps to reduce the size of routing tables.
RIP2 transmits the mask with each
route.This feature allows VLSM by passing the mask along with each route
so that the subnet is exactly defined.
RIP2 provides clear text and MD% encryption to authenticate the source of a routing update.
RIPs metric is hop count.The maximum hop count is 15.16 is considered to be an infinite metric.
Entire routing tables are broadcast every 30 seconds for RIP;60 seconds for IPX RIP.
If a router running RIP does not receive
an update from another router for 180 seconds,it marks the routes
served by the non-updating router as being invalid.
A RIP1 only and a RIP2 only router will not be able to exchange routing information.
There are differences between IPX RIP and IP RIP.
Novell RIP uses timer ticks and hops as metrics.
Novell RIP has a 60 second update timer.
IP RIP has a 30 second update timer.
IP RIP has a 180 second hold-down timer.
IGRP (Interior Gateway Routing Protocol) was produced by Cisco in the mid-1980s
Distance Vector
Increased Scalability (works better in large networks than RIP)
More sophisticated metric provide for
more accurate routing).Metrics
included:bandwidth,delay,reliability,load,and MTU.By default,omly
bandwidth and delay are used.Bandwidth and delay are not measured
values,but are set by the DELAY and BANDWIDTH commands.
Supports multiple paths (maintains up to six unequal cost paths).
Requires an autonomous system number.
It does not have t be registered, but all routers within an autonomous
system must use the same number to communicate. An “autonomous system”
is a set of routers under a common administration.
Supports Load balancing and load Sharing.
4,294.967,295 (over four billion) is considered to be an infinite metric.
255maximum hop count.
MTU (Maximum Transmission Unit);maximum
frame length in actetes of a L3PDU that is acceptable to all links on
the path.If an inbound router interface receives a frame that is larger
than the outbound router’s interface MTU,the router will fragment the
packet into units allowed by the outbound router interface.If the DF
(Don’t Fragment)bit is set,and the packet is too large for the
destination network,the packet will be dropped.ethernet has a MTU of
1500 bytes.
administrativeDistance is an integer
value used to determine a preference between two equal routing metrics
learned by different routing protocols.It is only important if multiple
routing protocols are in use in a single router.When this is true,both
routing protocols can learn routes to the same subnets.because the
metric values are different,there is no way to know which routing
protocol’s routes are better.This is also considered the rating of
trustworthiness.
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