redistribution ospf

mcsemcsemcse

i m new studing ccnp , i have 2 routers i want to redistribute between ospf ripv2 when i type ospf side redistribute rip metric here i have stuck how i ll decide to true metric its depend of the bandwith i have between 2 routers ???? lets say bandwith between them 100mbps what should be metric

tech-airman

mcsemcsemcse wrote:

i m new studing ccnp , i have 2 routers i want to redistribute between ospf ripv2 when i type ospf side redistribute rip metric here i have stuck how i ll decide to true metric its depend of the bandwith i have between 2 routers ???? lets say bandwith between them 100mbps what should be metric

mcsemcsemcse,

Questions:

1. What is the metric for RIPv2?
2. What is the metric for OSPF?

Plazma

Could you please rephrase this? It really is hard to understand what you are asking.

gojericho0

The metric for OSPF by default will be an external type E2 (N2 if NSSA) with a default-cost of 20. If you change the metric type to 1 it will also add the local cost calculations when determining the path metric.

mcsemcsemcse

lets say the bandwith is T1 OR E1 or 256kbps i wrote to know the cost 100mbps

---

link speed

if the defualt cost is 20 its consider the link 5mbps if i wrong plz correct it .
i dont have problem with cost my problem with metric i need to know calculate the metric to know what should i use metric when i m redistributing between ospf and rip i wanna redistribute 1 way ospf side

gojericho0

By default routers who will be receiving this redistributed route will only see cost 20 and link speed will not be a factor. It will use a higher administrative distance so it would not be as trustworthy as other routes in the same area.

Plazma

If you wanted the cost to increment, you would have to set the metric-type to 1 aka an E1 external route

tech-airman

mcsemcsemcse,

mcsemcsemcse wrote:

lets say the bandwith is T1 OR E1 or 256kbps i wrote to know the cost 100mbps

---

link speed

Please restate your "...lets say..." by being specific to the throughput.

mcsemcsemcse wrote:

if the defualt cost is 20 its consider the link 5mbps if i wrong plz correct it .

You asked to be corrected so the default cost of 20 is incorrect. Without you specifying which specific throughput you're talking about, I cannot give an accurate correction.

mcsemcsemcse wrote:

i dont have problem with cost my problem with metric i need to know calculate the metric to know what should i use metric when i m redistributing between ospf and rip i wanna redistribute 1 way ospf side

If you have a problem calculating the metric for OSPF, then you're having problems calculating cost because the metric for OSPF is cost.

Before you redistribute, you HAVE to understand how the metric for EACH of the routing protocols are calculated BY THEMSELVES. In your example, you mentioned RIP and OSPF. That's why in my previous post I asked you specifically two SEPARATE questions.

mcsemcsemcse

if the bandwith 1GBPS the default metric will work or its better if i change it the metric to 1 ?

gojericho0

It all depends on the design. If you only have one exit point into the different AS I would just leave it at E2

tech-airman

mcsemcsemcse wrote:

if the bandwith 1GBPS the default metric will work or its better if i change it the metric to 1 ?

mcsemcsemcse,

By default, the OSPF metric is based on the 100 Mbps FastEthernet throughput. That means the OSPF cost for a FastEthernet network segment will be 1. Unfortunately, since cost is an integer value, you can't have an OSPF cost of 0.001 for 1 Gbps GigaEthernet. That's why by default, the OSPF cost for a 1 Gbps GigaEthernet network segment will also be 1. This is the purpose of the auto-cost reference-bandwidth command so that you can change the reference default of 100 Mbps to another reference such as 1 Gbps or 10 Gbps.