When do we implement Static Routing

[sugaranderson1]

Hello,

A newbie here. I have tried to search in google on this but I cannot find the answer to my question.

I hope you can help me and shed some light. Your expert advise will be of great help

here's my question:

1. When do we implement static routing?

2. or what are the instances that we need to use this?

2. If I wanted to share files/other resources to remote office, is configuring static routing will work?

Thank you in advance!

Sugar

[Sergey Volgapkin™]

Hi.

1.1 When you have slow bandwidth links (for example dial-up), because dynamic routing updates consume bandwidth.

1.2 When necessary to reach a network accessible by one path. For example: when router connects to ISP – you need have static default gateway to ISP or you have stub network.

1.3 When you have slow CPU or memory, because dynamic protocols consume it.

2. You can use static route for add in routing table information about remote office (for have connection remote office).

I hope this information will be useful.

[sugaranderson1]

Hi Sergey,

Thanks for your reply and help.

I just want to confirm, if wanted to share files and other resources, can this be achieved by configuring static route?

Again, thank you.

Sugar

[John Blakley · Accepted solution]

Sugar,

It depends. The static route only lets the router know how to get to a certain subnet. The server that's sharing resources will be on a subnet, and the router on the other side will need to know how to get to it. It wouldn't control if files could be shared or not though.

Example. Let's say that you have 2 routers: 192.168.1.0 and 192.168.2.0. The routers connect on 10.10.10.0/30. All of your users are in 192.168.1.0 and your servers are in 192.168.2.0. You have a web and ftp server at address 192.168.2.50.

192.168.1.0 (RouterA) 10.10.10.1 <--------> 10.10.10.2 (RouterB) 192.168.2.0

The routers don't know about each other's internal subnets. Without a routing protocol advertising them, they'll need some way to know how to get to the other subnet. You'll need 2 static routes; one on each router:

On RouterA:

ip route 192.168.2.0 255.255.255.0 10.10.10.2

On RouterB:

ip route 192.168.1.0 255.255.255.0 10.10.10.1

As you can see, it doesn't control file sharing or anything but it basically tells the router how to get to the other subnet.

HTH,

John

[Richard Burts · Accepted solution]

Sugar

It is difficult to make absolute statements that static routing will always work, because some situations are different and may impact the use of static routing. But in general it is safe to assume that you could use static routing to be able to share files and things like that.

I would explain it in this way:

- in general we can assume that static routing works and that it is the most simple and basic level of establishing network connectivity. It is almost always available and is the fall back position when we choose not to use dynamic routing protocols.

- in general we can assume that dynamic routing protocols are an alternative to static routing and that dynamic routing protocols offer some advantages over static routing.

So the question becomes what are the advantages of dynamic routing and when we might choose dynamic routing protocols over static routing. The advantages include:

- if the number of routes in the network gets large it becomes an administrative burden to keep track of all of them and to manually configure all the routes.  I have a customer that has well over 2,000 routes in their network and networks of that size would be extremely difficult to maintain static routes.

- if there are more than one way to get to a destination and we want to choose the optimum path. We might be able to do that with static routes, but the dynamic routing protocol does it automatically and much more efficiently.

- if we want to be able to react to changes that take place in the network. I had a customer once who wanted to be very much in control of what happened in their network. And their policy was to use only static routes. Every time that a network connection went down they had to manually discover the problem and then to manually make changes to use a different path throgh the network. I thought it was not very efficient, but it did satisfy their desire to maintain great control over the network. A dynamic routing protocol will automatically detect changes in link status in the network and will automatically make changes in the routing table to accommodate maintaining the optimum path.

From what I understand from your other post it appears that your network is fairly small. It may not have very many alternate paths to destinations, and there may not be that many choices of how to find the path to the destinations. So it sounds like static routing would be a satisfactory solution for you.

HTH

Rick

[sugaranderson1]

Hi Rick,

Thank you for your explanation. I appreciate it.

I am now considering configuring a site to site VPN like what you have suggested in my other post.

again, thank you.

Sugar

[paolo bevilacqua]

Are you the end use trying to setup a small office? Because from your questions so it seem.

Maybe is better you explain what your real necessity it is.

[sugaranderson1]

Hi Paolo,

thanks for the reply.

we have a small office and we wanted to share files/resources on our remote office. im thinking if static routing would be the solution in connecting our 2 offices. our main objective is to be able to share resources on our 2 offices.

thanks again.

Sugar

[John Blakley · Accepted solution]

Sugar,

If you don't have a point-to-point connection to the other office or an MPLS connection through a provider and are only using standard internet connections, you're going to need to implement IPSec tunnels to have the 2 locations talk to each other. It's going to get a lot more complicated than just a static route.

John

[sugaranderson1]

Hi John,

Thank you very much for your reply and help

I now have a better understanding on what to do. I thought I can just simply do a static route to get our 2 office to communicate to each other.

I may have to do a site to site VPN. I'll look for a CISCO router model that will meet this requirement.

Again, thank you.

Sugar

[Richard Burts · Accepted solution]

Sugar has another post asking about connecting the two offices and in that thread we pretty clearly suggested a site to site VPN was the solution that they need. Use this link to see that thread

https://supportforums.cisco.com/message/3639755#3639755

Assuming that each office has a fairly small and simple topology, and assuming that each office has a static IP then I believe that configuring a site to site VPN should be fairly straightforward. And I believe that static routing is all that they need. Each office may need some static routes for subnets within the office (if there are subnets that are not locally connected on the main router), and would need static route(s) for the subnets in the other office, and would need a static default route to the Internet Service Provider. I would think that this would be adequate for their needs.

But as John points out it is more complicated than just configuring some static routes. There needs to be a site to site VPN configured also.

HTH

Rick

[sugaranderson1]

Hi Rick,

Thanks again for your help again and for clearing this.

Yes, you are correct our office is only a small network. I will do a static route and site to site vpn to communicate our 2 offices on a different location. and will probably buy a cisco vpn router.

again, thank you very much. i there is additional things that needs to do, kindly let me know.

Sugar

[paolo bevilacqua]

Absolutely, Richard.

May I add that the best option would be to select a reputable partner or Certfied Cisco partner for the task.

[alikcb]

when we are certain about the destination.
when we don't need to worry about updating the routing often.
when a limited configuration is required.
when we are aiming for specific alternation (known) in the RT.
configure and forget scenarios.