Flashcards in Chapter 10 Deck (45):
what is Routing protocols?
Routing protocols determine the best path, or route, to each network. That route is then added to the routing table. A primary benefit of dynamic routing protocols is that routers exchange routing information when there is a topology change.
what is an autonomous system (AS)?
An autonomous system (AS)—otherwise known as a routing domain—is a collection of
routers under a common administration. Typical examples are a company’s internal network
and an ISP’s network. Because the Internet is based on the autonomous system concept,
two types of routing protocols are required: interior and exterior routing protocols.
what is the interior routing protocol?
■ Interior gateway protocols (IGP): Used for intra-autonomous system routing, that is,
routing inside an autonomous system
what is the exterior routing protocol?
■ Exterior gateway protocols (EGP): Used for inter-autonomous system routing, that is,
routing between autonomous systems
what is administrative distances (AD)?
Administrative distance is the feature that routers use in order to select the best path when there are two or more different routes to the same destination from two different routing protocols.
an AD is an integer from 0 to ___
when the Ad is 0 what dose that mean ?
the most trusted route, and that mean that this route is the one that the router is going to use.
administrative distance of 255 mean what?
it means no traffic is allowed to be pass via this route.
if a router receives 2 updates listing the same remote network, what is going to be the first thing that the router will check?
if a router receives 2 updates listing from 2 routers for the same remote network, it mean 2 ADs which one is the router going to choose?
the router will choose the one with a lower AD and that router will be placed in the routing table.
what bis a hop count?
The hop count refers to the number of intermediate devices ... some routing protocols such as RIP use hop count as their sole metric.
how do routing protocol perform loading balance?
a router will send a packets down each link to test for the best one
when do routing protocol perform a loading balance?
they do it when a router get the same remote network from different routers, with the same AD's and the same hop counts.
what is the default AD for connected interface?
what is the default AD for Static route?
what is the default AD for external BGP?
what is the default AD for internal EIGRP?
what is the default AD for ICRP?
what is the default AD for OSPF?
what is the default AD for ISIS?
what is the default AD for RIP?
what is the default AD for External EIGRP?
what is the default AD for Internal BGP?
what is the default AD for an unknown router source?
we can change the AD of a static router. T/F
the static router have the AD of 1 by default. T/F
what are the 3 classes of routing protocols?
Distance vector protocols (a vector contains both distance and direction), such as RIP, RIPv2 and interior gateway routing protocol( IGRP). Distance vector determine the path to remote networks using hop count as the metric. A hop count is defined as the number of times a packet needs to pass through a router to reach a remote destination.
Link state protocol:
is also called shortest path first protocol.
Link state routing is a complex routing technique in which each router shares information with other routers about the reachability of other networks and the metric to reach the other networks in order to determine the best path. Routing is the process of moving packets across a network from one host to a another.
each router create 3 separate tables
in the link state protocol there are 3 tables, what are in these tables/
one table keeps track of directly attached neighbors
one determines the topology of the entire internetwork.
and one is used to the actual routing table.
some examples of the Link state protocol:
OSPF and ISIS
Short for Open Shortest Path First, OSPF is an IP link-state network routing protocol that helps determine the most efficient path to the next hop in a network.
Intermediate System to Intermediate System (IS-IS) is a routing protocol designed to move information efficiently within a computer network, a group of physically connected computers or similar devices. It accomplishes this by determining the best route for datagrams through a packet-switched network.
Link state protocol send updates containing the state of their own links to all other routers on the network. T/F
a hybrid protocol uses both distance vector and Link state protocol.
what are the 2 hybrid protocol that we need to know about?
Enhanced IGRP (EIGRP) and the BGP
EIGRP makes decisions based on metric information it receives from neighbors, and it employs some of the mechanisms of link-state protocols.
Border Gateway Protocol (BGP)
Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information between autonomous systems (AS) on the Internet.
what is an autonomous system?
an autonomous system is a collection of networks under a common administrative domain.
A First Hop Redundancy Protocol (FHRP)
it is a computer networking protocol which is designed to protect the default gateway used on a subnetwork by allowing two or more routers to provide backup for that address; in the event of failure of the/an active router, the backup router will take over the address, usually within a few seconds. In practice, such protocols can also be used to protect other services operating on a single IP address, not just routers.
two Redundancy protocol we need to know. what are they?
Hot standby Router Protocol (HSRP)
Virtual router Redundancy Protocol ( VRRP)
HSRP and VRRP are not routing protocols. True/False?
HSRP and VRRP are not routing protocols as they do not advertise IP routes or affect the routing table in any way.
what is the Hot Standby Router Protocol (HSRP)?
is a Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway, it has up to 8 routers, The protocol establishes a framework between network routers in order to achieve default gateway failover if the primary gateway becomes inaccessible, in close association with a rapid-converging routing protocol like EIGRP or OSPF. HSRP routers send multicast Hello messages to other routers to notify them of their priorities (which router is preferred) and current status (Active or Standby).
The Virtual Router Redundancy Protocol (VRRP):
The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.
The protocol achieves this by creation of virtual routers, which are an abstract representation of multiple routers, i.e. master and backup routers, acting as a group. The default gateway of a participating host is assigned to the virtual router instead of a physical router. If the physical router that is routing packets on behalf of the virtual router fails, another physical router is selected to automatically replace it. The physical router that is forwarding packets at any given time is called the master router.