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Routing Table

can anybody tell me how many static routes can be configured on a a Cisco router between a source and a destination?

6 REPLIES
Green

Re: Routing Table

The limit would be determined by the amount of RAM you have to build the routing table.

Larger routers --> more RAM --> more routes

There are other practical considerations (like CPU and other configured features, like ACLs and NATs), but the real limit is RAM.

What have you got, and how many routes are you trying to configure?

Good Luck

Scott

Re: Routing Table

George,

I dont know the exact amount, but i tried it in my lab by connecting 8 links between the routers and all the 8 routes were entered intthe routing table.

below is the route table

R1#sh ip route

Gateway of last resort is not set

17.0.0.0/24 is subnetted, 1 subnets

S 17.16.100.0 [1/0] via 8.8.8.2

[1/0] via 7.7.7.2

[1/0] via 6.6.6.2

[1/0] via 5.5.5.2

[1/0] via 4.4.4.2

[1/0] via 3.3.3.2

[1/0] via 2.2.2.2

[1/0] via 1.1.1.2

1.0.0.0/24 is subnetted, 1 subnets

C 1.1.1.0 is directly connected, Serial1/0

2.0.0.0/24 is subnetted, 1 subnets

C 2.2.2.0 is directly connected, Serial1/1

3.0.0.0/24 is subnetted, 1 subnets

C 3.3.3.0 is directly connected, Serial1/2

4.0.0.0/24 is subnetted, 1 subnets

C 4.4.4.0 is directly connected, Serial1/3

5.0.0.0/24 is subnetted, 1 subnets

C 5.5.5.0 is directly connected, Serial2/0

6.0.0.0/24 is subnetted, 1 subnets

C 6.6.6.0 is directly connected, Serial2/1

7.0.0.0/24 is subnetted, 1 subnets

C 7.7.7.0 is directly connected, Serial2/2

8.0.0.0/24 is subnetted, 1 subnets

C 8.8.8.0 is directly connected, Serial2/3

In case of routing protocols the MAx amount mostly is 6.

But when you have more than 6 links, you can multilink a pair of 6 links into one and go upto 36 links logically.

The multilink concept can be applied to static routes too

But in the end it all depends upon the processing power your router has got.

HTH, rate if it does

Narayan

New Member

Re: Routing Table

But how do you directly connect the IP to the serial interface?

Re: Routing Table

Can you please elaborate on your question

Narayan

Green

Re: Routing Table

There are two forms of the command to create a static route:

IP ROUTE a.b.c.d m.m.m.m ga.gb.gc.gd

IP ROUTE a.b.c.d m.m.m.m interface

In the first instance, you provide the net/subnet (and mask) of the target network (a.b.c.d m.m.m.m) the next hop address (ga.gb.gc.gd) and an optional metric (for cases when you want a "floating static" to cover a path in case the primary link drops, for example).

The router determines the interface automatically, based on the interface's address ... the "next hop" would be in the same net/subnet as the router's egress interface.

In the second instance, you explicitely tell the router to send all traffic for the target net/subnet out a particular interface (and an optional metric, for the same reasons as the first instance).

The router doesn't know or care what's on the other side ... you have directed it to pump all the traffic for a.b.c.d with a mask of m.m.m.m to the specified interface ... .whether it's valid or not, that's where the traffic will go.

The advantage of one over the other relates to how the routing table reacts when the path becomes invalid, I believe.

Good Luck

Scott

New Member

Re: Routing Table

Narayan, You have understood the Qn correctly. I hope the number of ststic routes for a destination can go beyond 8 also and the router will load share among these links.

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