Overview: Layer 3 issues include problems at the network layer with routed protocols as well as routing protocols Study Notes: Layer 3 network layer issues Physical and Data link layers are working properly Network connectivity issues Possibly cannot ping Incorrect IP or subnet mask settings No gateway configured Misconfigurations Connectivity issues Neighbor issues Topology […]
Overview: RIPv2 is an enhancement over RIPv1 in that RIPv2 overcomes three main limitations. RIPv2 accommodates discontiguous network designs, supernetting and VLSM. Study Notes: RIPv2 is an enhancement over RIPv1 RIPv2 is encapsulated in a UDP segment on port 520 RIPv2 can carry up to 25 ruotes RIPv2 includes a subnet mask field allowing […]
Overview: EIGRP for IPv6 functions the same as EIGRP for IPv4 only it uses IPv6 addresses and some of the commands are different. Study Notes: Configuration commands to use with EIGRP for IPv6 config t ipv6 unicast-routing ipv6 router eigrp eigrp router-id 1.1.1.1 no shutdown Ctrl+Z config t interface f0/0 ipv6 eigrp 1 Ctrl+Z […]
Overview: Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary advanced distance vector dynamic routing protocol. Study Notes: EIGRP uses the Diffusing Update Algorithm (DUAL) Fast convergence Easy on processor Incremental updates EIGRP is an Advanced Distance vector protocol Combines the best of Distance Vector with Link State protocols, but is considered a […]
Overview: Auto-cost Reference Bandwidth is the command used to modify the OSPF metric. Study Notes: Auto-cost reference bandwidth is used to modify the OSPF metric The OSPF metric is cost Cost is calculated by dividing 100 by the bandwidth in Mbps Cost = 100/(bw in Mbps) Any result less than 0 will use a […]
Overview: A passive interface prevents sending OSPF messages out interfaces that are not connected to another OSPF router. Study Notes: Passive interfaces help to more efficiently use bandwidth Passive interfaces help to more efficiently use router resources Passive interfaces lessen the security risk Passive interfaces can be set per interface that is enabled for […]
Overview: OSPFv3 has the same functionality as OSPFv2, but uses IPv6 addresses to communicate with OSPFv3 peers. Study Notes: OSPFv3 uses the same SPF algorithm as OSPFv2 OSPFv3 has a separate process than OSPFv2 OSPFv3 maintains separate neighbor tables, topology tables and routing tables from OSPFv2 Similarities Link State SPF algorithm Metric is cost […]
Overview: Open Shortest Path First version 2 (OSPFv2), is a non-proprietary link-state routing protocol that is typically used within an autonomous system (otherwise known as an interior gateway protocol). The v2 simply means you are using IPv4 addresses. Study Notes: OSPF is a Link-state routing protocol Dijkstra’s Shortest Path First algorithm is used to […]
Overview: A wildcard mask is a mask of bits (a bitwise operation) that indicates which parts of an IP address are available for examination. Study Notes: A bitwise operation is one that compares two bits with each other to come up with a result – IP and mask (subnet mask, wildcard mask, etc) Mask […]
Overview: A floating static route is a static route with an administrative distance higher than that of the routing protocol in use. In this way, the floating static route will only appear in the routing table if the existing static or dynamic route is lost. Study Notes: Floating static routes are static routes with the […]