Dynamic Routing Between Private Networks

[paxpaw0202]

Hi

I would like some advice on how to redistribute routes between three independently managed private networks.

Currently: See attachment

The two buildings managed by Company 1 are connected by 4x1GB fibre channel ports on Cisco 3750G Standard Image switches. Static routing is used between the two building and static routes are used to direct traffic to Company 2 and Company 3 via routers managed by their respective companies. No NAT is required as all three companies use separate private address schemes.

Network Improvements: See attachment

To increase network resilience Companies 2 and Company 3 are planning on installing new routers in building 2. Companies 2 and 3 use Dynamic routing protocols on their internal network.  Incoming and outgoing resilience is required in all three companies.  There is no direct connectivity between Company 2 and 3.

I would like the following questions answered:

1. Is dynamic routing needed in Company 1?

2. Given that only 4 devices are managed by Company 1 will RIPv2 work? NB. Company 2 and 3 have very large networks (3000+ sites).

3. Would route redistribution be best performed on Company 2 and 3’s CE routers?

4. How can route redistribution be controlled by Company 1?

[sansarav720e]

HI Pax ,

            Though your company 1 does'nt have any routing protocol till now , It better to understand what is dynamic routing protocol is running on company 2 and company 3 , According you can decide your routing protocol for your company 1 .

          If you both company 2 and company 3 has a dynmaic routing protocol as EIGRP , you can configure EIGRP on company 1 and make it as a stub area , which will recieve only default route . If you want have specfic route from both companies 2 & 3 then you can disable stub .

          Instead of having redistrubtion you can adopt same routing protocol ,whatever being used on your compamy 2 & Company 3 , becoz u dont have a bigger setup running on your company 1. probably you have 2 - 4 IP stack operating on this .

HTH

San

[paxpaw0202]

Hi

Thanks for the reply.  Unfortunately I am not sure as to the exact routing protocols used

In Company 2 - I think they use BGP, but they have offered to redistribute the routes into any routing protocol Company 1 wants.

In Company 3 - I think they use OSPF, but again they have offered to redistribute these routes into the desired routing protocol.

The reason why Company 1 would like to use RIPv2 is because they only have 3750G Standard Image switches which are not capable of using OSPF, EIGRP or BGP.  Company 1 will upgrade these switches if required, however they would prefer not to.  I am concerned that RIPv2 would not be capable given the size of the networks in companies 2 and 3. I am also concerned that Company 1 will not have control over the routing if redistribution occurs at Companies 2 and 3’s CE routers.

[meperuma]

Hi Pax,

If I understood  your requirement & topology correctly

1. SIMPLE method: You can use the RIP on the COM1 and redistribute the summarised static route via RIP to COM1. COm2 & COM3 can do the same with their own routing protocols.  I assume all there COMs are different network. SO, RIP will handle the dynamic routing on COM1 and elimiate  bit on the opertaional burden and troubleshooting. but static route may give trouble in a redundancy scneraio or port hung   or metro ethernet circutis ( as some times fault is not relayed end-to-end)

2. If you see any growth and business needs, I prefer to separate all three companies using EBGP protocol. so that you can do better  route control and manipulation.

HTH

[paxpaw0202]

Hi

Thanks again for the reply. To clarify could anyone answer the following questions:

1. Is dynamic routing needed in Company 1?

2. Given that only 4 devices are managed by Company 1 will RIPv2 work, even though routes will be shared with Company 2 and 3 that have very large networks?

3. Would route redistribution be best performed on Company 2 and 3’s CE routers?

4. If route redistribution is performed on Company 2 and 3’s router, how can route redistribution be controlled by Company 1?

I have added some simplified network addresses to the attached diagram, so that a sample configuration of the switches can be created to demonstrate the answers to the above questions.