BROCADE IP PRIMER

Console49F Link 50F1Power1F 2F 3F 4F325476981110131215141716191821202322252427262928313033323534373639384140434245444746 4849F Link 50FPower11F 2F 3F 4F32Console5476981110131215141716191821202322252427262928313033323534373639384140434245444746 4849F Link 50FPower11F 2F 3F 4F32Console5476981110131215141716191821202322252427262928313033323534373639384140434245444746 48Routing Information Protocol (RIP)On Brocade switches, you have the option to turn off poison reverse and use adifferent method: split horizon. Split horizon is very similar. The difference isthat instead of advertising the routes as unreachable, it just doesn't advertisethem at all. If Switch B were to have learned a route for 172.16.0.0/16 fromSwitch A, Switch B will not advertise a route for 172.16.0.0/16 back to SwitchA. It will to Switch C, but not to A.Split Horizone2192.168.1.2/30Switch Be2192.168.2./30e1192.168.1.1/30Switch A“Hey, I know how to getto 172.16.0.0/24”ve20172.17.0.1/24Host B172.17.0.10/24“Hey, I know how to getto 172.16.0.0/24”e1192.168.2.1/30Switch Cve10172.16.0.1/24e2192.168.3.1/30e2192.168.3.2/30ve30172.18.0.1/24Host A172.16.0.10/24Host C172.18.0.10/24RIP version 1 vs. RIP version 2In 1994, RIP version 2 was introduced, and it is typically the preferred versionof RIP to run. There are two main improvements on the original RIP:• RIPv2 is classless. RIPv1 is classful.• RIPv2 provides authentication between routers using a shared passwordhashed by MD5Discussion of the authentication goes beyond the scope of this book, but let'stake some time to discuss the classless versus classful. This is a big deal, andthe principle reason why RIPv2 is preferred.Flip back to Chapter 2. Don't worry, I'll wait. Classful means that you don't payattention to the subnet mask. You simply rely on the Class system to determineyour mask. For example, if the address's first octet is, say, 10 (the full addressbeing, say, 10.1.1.3), a classful protocol will assume a Class A mask(255.0.0.0). It doesn't understand the concept of subdividing beyond theClass.Classless means we've got full rein to subdivide however we see fit. The idea isthat RIPv1 is Classful. It doesn't send subnet mask information with theroutes. It just sends the network address and the receiving router assumes adefault subnet mask. RIPv2 includes the network address and the subnetmask information. It is Classless. It is not bound to use only the default subnetmasks. It can use whatever the engineer configured.In our examples with Switch A, B, and C, this isn't too dangerous a circumstance.You should know, that the 192.168.x.x routes will be advertised as fullClass Cs instead of /30s. This means that they'll be advertised as192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24. This is okay for now,but if we want to use, say, some subnets like 10.1.1.0/24, 10.2.2.0/24, andBrocade IP Primer 233