Search results
Results from the WOW.Com Content Network
In other words, a holddown keeps a router from receiving route updates until the network appears to be stable—until either an interface stops changing state (flapping) or a better route is learned. Holddowns are usually implemented with timers. If the router detects that a network is unreachable, the timer is started.
A route is considered unreachable if the hop count exceeds the maximum allowed. Route poisoning is a method of quickly forgetting outdated routing information from other router's routing tables by changing its hop count to be unreachable (higher than the maximum number of hops allowed) and sending a routing update.
The flush timer controls the time between the route is invalidated or marked as unreachable and removal of entry from the routing table. By default the value is 240 seconds. This is 60 seconds longer than Invalid timer. So for 60 seconds the router will be advertising about this unreachable route to all its neighbours.
Null routes are typically configured with a special route flag; for example, the standard iproute2 command ip route allows to set route types unreachable, blackhole, prohibit which discard packets. Alternatively, a null route can be implemented by forwarding packets to an illegal IP address such as 0.0.0.0 , or the loopback address .
Destination network unreachable 1: Destination host unreachable 2: Destination protocol unreachable 3: Destination port unreachable 4: Fragmentation required, and DF flag set 5: Source route failed 6: Destination network unknown 7: Destination host unknown 8: Source host isolated 9: Network administratively prohibited 10: Host administratively ...
Split-horizon routing with poison reverse [4] is a variant of split-horizon route advertising in which a router actively advertises routes as unreachable over the interface over which they were learned by setting the route metric to infinite (16 for RIP). The effect of such an announcement is to immediately remove most looping routes before ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
The Neighbor Discovery Protocol (NDP), or simply Neighbor Discovery (ND), is a protocol of the Internet protocol suite used with Internet Protocol Version 6 (IPv6). [1]: §1 It operates at the internet layer of the Internet model, [2] and is responsible for gathering various information required for network communication, including the configuration of local connections and the domain name ...