18.07.2013 Views

Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

Sidewinder G2 6.1.2 Administration Guide - Glossary of Technical ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Appendix C: Configuring Dynamic Routing with OSPF<br />

OSPF processing on a <strong>Sidewinder</strong> <strong>G2</strong><br />

604<br />

Figure 239: OSPF areas<br />

OSPF<br />

processing on a<br />

<strong>Sidewinder</strong> <strong>G2</strong><br />

Autonomous Systems can be large. It is not necessary for the whole AS to<br />

need to know "everything" about routes. Each AS may be broken down into<br />

areas. All routing information must be identical within an area. Routing<br />

between areas goes through a "backbone." All routers on a backbone have to<br />

be able to communicate with each other. Since they belong to the same area<br />

(area 0 <strong>of</strong> a particular AS), they also all have to agree. Area Border Routers<br />

(ABRs) will have one interface defined to run in the backbone area. Other<br />

interfaces can then be defined to run in a different area.<br />

Take a look at a sample configuration. Figure 239 shows a large internal<br />

network and backbone terminating at a router.<br />

area 0 (backbone)<br />

Complicated<br />

Network<br />

Autonomous system (AS)<br />

R<br />

ABR<br />

area n (8.8.8.8)<br />

Complicated<br />

Network<br />

ASB<br />

EGP<br />

BGP<br />

Stub areas are areas where there is a single exit point. An OSPF router sends<br />

"summary" LSAs into the stub that point back to that router as the default<br />

router for the stub area.<br />

For more information on OSPF and Internet routing, check with your router<br />

vendor. The following books may also be useful:<br />

• Routing in the Internet, 2nd edition by Christian Huitema, Prentice Hall<br />

(2000)<br />

• Cisco Router OSPF: Design and Implementation <strong>Guide</strong>, by William R.<br />

Parkhurst (Cisco <strong>Technical</strong> Expert), McGraw Hill (1998)<br />

OSPF processing is done via a <strong>Sidewinder</strong> <strong>G2</strong> server process called gated. To<br />

implement OSPF processing on the <strong>Sidewinder</strong> <strong>G2</strong>, a gated server process<br />

must be configured, enabled, and started in the burb expecting to handle<br />

OSPF broadcasts. Only one gated may be started per burb, but that gated<br />

will handle all network interfaces within that burb.<br />

The <strong>Sidewinder</strong> <strong>G2</strong> currently runs version 3.6 <strong>of</strong> gated. This is the most recent<br />

freely available version <strong>of</strong> gated available from the OSPF Consortium and it's<br />

successor, NextHop.<br />

This release <strong>of</strong> OSPF on the <strong>Sidewinder</strong> <strong>G2</strong> runs gated as an “intra-area”<br />

router. That means all interfaces that are configured to run OSPF exist in the<br />

same OSPF area.<br />

Note: Support for the <strong>Sidewinder</strong> <strong>G2</strong> running as an ABR will come in a future<br />

release.<br />

R

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!