Routing table entries that are subnetted are level 1 parent routes but do not meet either of the two requirements to be ultimate routes. Ultimate routes do not have to be classful network entries. By default, dynamic routing protocols forward messages across a network without authenticating the receiver or originator of traffic.
Static routes increase in configuration complexity as the network grows larger and are more suitable for smaller networks. Static routes also require manual intervention when a network topology changes or links become disabled.
The router learned, via RIP, that This means that RIP version 2 is running on both routers and that the command no auto-summary has been applied on the neighbor router. RIPv2 has an administrative distance of and this router will advertise all connected networks to the neighbor via The command being entered by the engineer will cause RIPv2 to activate on the interface for the If RIPv1 is configured, the router will send only version 1 updates, but will listen for both version 1 and version 2 updates.
If RIPv2 is configured, the router will send and listen to only version 2 updates. Routes in a routing table are manually created or dynamically learned. The new version of the exam focuses on IP. So what do you need to know about IP other than that is how all your node to node communication will occur? Make sure you know how to subnet! If you cannot subnet or are weak in this area , you stand a fairly good chance of failing this exam.
Understanding how to subnet will not guarantee that you will pass this exam, but not understanding subnetting will guarantee that you fail. If you have an IP address and its subnet mask, could you tell the subnet ID of that host, the last useable host on that subnet, the subnet broadcast address, in addition to the number of possible subnets and hosts per subnet? Designated routers establish adjacencies with all routers on that network segment.
This is to reduce broadcasts from all routers sending regular hello packets to its neighbors. The DR sends multicast packets to all routers that it has established adjacencies with. Each router is assigned a router ID, which is the highest assigned IP address on a working interface. An intermediate system is a router and IS-IS is the routing protocol that routes packets between intermediate systems.
Neighbor routers on point to point and point to multipoint links establish adjacencies by sending hello packets and exchanging link state databases.
IS-IS routers on broadcast and NBMA networks select a designated router that establishes adjacencies with all neighbor routers on that network. The designated router and each neighbor router will establish an adjacency with all neighbor routers by multicasting link state advertisements to the network itself. IS-IS uses a hierarchical area structure with level 1 and level 2 router types. Level 1 routers are similar to OSPF intra-area routers, which have no direct connections outside of its area.
Level 2 routers comprise the backbone area which connects different areas similar to OSPF area 0. The difference with IS-IS is that the links between routers comprise the area borders and not the router. Each IS-IS router must have an assigned address that is unique for that routing domain. An address format is used which is comprised of an area ID and a system ID. There is support for variable length subnet masks, which is standard with all link state protocols.
Note that IS-IS assigns the routing process to an interface instead of a network. Border Gateway Protocol is an exterior gateway protocol , which is different from the interior gateway protocols discussed so far.
Exterior gateway protocols such as BGP route between autonomous systems, which are assigned a particular AS number. AS numbers can be assigned to an office with one or several BGP routers. The difference is their autonomous systems refer to a logical grouping of routers within the same administrative system.
They are all managed by the company for defining route summarization, redistribution and filtering. BGP is utilized a lot by Internet Service Providers ISP and large enterprise companies that have dual homed internet connections with single or dual routers homed to the same or different Internet Service Providers. BGP will route packets across an ISP network, which is a separate routing domain that is managed by them.
There are 10 defined attributes that have a particular order or sequence, which BGP utilizes as metrics to determine the best path to a destination. Companies with only one circuit connection to an ISP will implement a default route at their router, which forwards any packets that are destined for an external network.
Once that is finished, incremental updates are sent with topology changes. Data traffic congestion does not directly influence routing protocol behavior. The RIPv2 routing protocol supports routing protocol authentication to secure routing table updates between neighbors. Link-state protocols have the following disadvantages: Memory Requirements — Creating and maintaining the link-state database and SPF tree. Processing Requirements — The SPF algorithm requires more CPU time than distance vector algorithms because link-state protocols build a complete map of the topology.
Bandwidth Requirements — Link-state packet flooding can adversely affect the available bandwidth on a network. Link-state routing protocols have their advantages and disadvantagea. The advantages are that each router builds a topological map; there is fast convergence; and the LSPs are sent only when there is a change in topology. The disadvantages are the requirements of router and bandwidth resources because of the complexity of the link-state routing protocols.
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