Ch19-RIPv2 Flashcards
A means for one router to choose between multiple routes to reach the same subnet when those routes were learned by different routing protocols. The lower this value, the better the source of the routing information
Administrative distance
The logic behind the behavior of some interior routing protocols, whose algorithms call for each router to send its entire routing table in each update, but only to its neighbors.
distance vector
A routing protocol that was designed to exchange routing information between different autonomous systems
Exterior gateway protocol
A routing protocol designed for use within a single organization
Interior gateway protocol
A unit of measure used by a routing protocol to determine the best route for traffic to use to reach a particular destination
metric
A reference to any routing protocol’s messages in which it sends routing information to a neighbor
routing update
A network topology in which subnets of network X are not separated by subnets of any other classful network
contiguous network
A network topology in which subnets of network X are separated by subnets of other classful network
discontiguous network
A routing protocol feature in which the router the sites at the boundary between different classful networks will advertise a route for one entire classful network into the other classful network, and vise versa
autosummarization
With a routing protocol, a router interface for which the routing protocol is enabled on the interface, but for which the routing protocol does not send routing protocol messages out that interface
passive interface
A list of routes in a router, with each route listing the destination subnet and mask, the router interface out which to forward packets destined to that subnets and as needed, the next-hop routers IP address
routing table
The metric used by the RIP routing protocol, with each router sitting between the source and destination subnet adding to that metric
hop count
Command reference: Global command that moves the user into RIP configuration mode
router rip
Command reference: RIP subcommand that lists a classful network number enabling RIP on all interfaces in that classful network
network network-number
Command reference: RIP subcommand that sets the RIP version to version 2
version 2
Command reference: RIP subcommand that tells RIP not to advertise RIP updates on the listed interface
passive-interface int-id
Command reference: RIP subcommand that changes the default setting on RIP-enabled interfaces to be passive instead of not passive
passive-interface default
Command reference: RIP subcommand that overrides a default passive setting per the passive-interface default command for the listed interface
no passive-interface int-id
Command reference: RIP subcommand that toggles the auto summarization feature of RIP
[no] auto-summary
Command reference: RIP subcommand that sets the number of equal-metric routes for the same subnet that RIP will add to the routing table
maximum-paths number
Command reference: RIP subcommand that causes RIP to advertise a default route, assuming the local route already has a default route in its routing table
default-information originate
Command reference: Interface subcommand that causes a router to act as a DHCP client, learning the IPv4 address to use on an interface and dynamically learning a default route that uses the DHCP-announced default gateway address as the next-hop IP in a static route
IP address DHCP
Command reference: Lists one line per router interface, including the IP address and interface status; an interface must have an IP address and be in an “up/up” state before RIP begins to work on the interface
show ip interface brief
Command reference: Lists the routing table, including RIP-learned routes (an optionally, only RIP-learned routes)
show ip route [rip]
Command reference: Lists details about the route the router would match for a packet sent to the listed IP address
show ip route [ip-address]
Command reference: Lists information about the RIP configuration, plus the IP address of neighboring routers from which the local router has learned routes
show ip protocols
Command reference: Lists one line per router interface, including the IP address and interface status
show ip rip database
When comparing routing protocols, what four points should be considered?
- Underlying algorithm (distance vector or link state?) 2. Usefulness of the metric (lower the metric, the better the choices made by the routing protocol) 3. Speed of convergence (how long to notice changes? how long to fully update all routing tables?) 4. Public standard or vendor-proprietary (affects interoperability)
Is a hop-count metric a feature of RIPv1, RIPv2, or both?
both
Is a max hop count of 15 hops a feature of RIPv1, RIPv2, or both?
both
Which RIP version sends the full routing table in every update message?
both
Which RIP version uses Split Horizon?
both
Which RIP version makes use of route poisoning to note failed routes?
both
When a RIP router sends a poisoned route, how does the receiving router know?
The poisoned route is advertised with an infinite metric, which for all RIP versions is a hop-count of 16.
What’s the maximum hop-count supported by RIP?
15
Which RIP versions support VLSM?
RIPv2
Which RIP versions send subnet masks in routing updates?
RIPv2, as only version 2 supports VLSM
Which RIP versions support manual route summarization?
RIPv2
Which RIP versions send routing updates via multicast?
RIPv2
To what address are RIPv2 routing updates sent?
224.0.0.9
Which RIP versions support router authentication?
RIPv2
Consider the following partial configuration:
router rip version 2 network 10.0.0.0 network 172.16.0.0
int fa0/0 ip address 10.1.1.1 ... int fa0/1 IP address 172.16.1.1 ... int fa0/2 IP address 172.16.2.1 ... int fa0/3 ip address 192.168.0.1 ...
Which interfaces will send and receive RIP updates?
fa0/0, fa0/1, and fa0/2. Since no network statement was configured for network 192.168.0.0, RIP will not be enabled on interface fa0/3
Describe 3 actions RIP takes once enabled on an interface
- Sends routing updates on that interface 2. Listens for routing updates on that interface 3. Advertises the subnet connected to that interface
What major function is associated with the command show ip route [rip]?
Routes Lists all routes learned [by RIP]
What major function is associated with the command show ip protocols?
Configuration RIP configuration can be derived from the command output, which also lists IP addresses of neighboring RIP routers from which the local router has learned routes.
What major function is associated with the command show ip rip database?
Best Routes Command output lists the prefix/length of all the best routes known to the route, including routes learned from neighbors and connected routes with RIP-enabled interfaces
Analyze the following single line of output from the show ip route command:
R 192.168.2.0/24 [120/1] via 192.168.5.2 00:00:21 Serial 0/0/0
R: Route source (in this case, learned via RIP) 192.168.2.0 ...to Network 192.168.2.0 /24 subnet mask 120 administrative distance 1 metric 192.168.5.2 ...via next-hop router @ 192.168.5.2 00:00:21 update timer ("last heard") Serial0/0/0 exiting from Serial0/0/0What is the administrative distance for a connected route?
0
What is the administrative distance for a static route?
1
What is the administrative distance associated with EIGRP?
90
What is the administrative distance associated with OSPF?
110
What is the administrative distance associated with RIP, both versions 1 and 2?
120
What is the administrative distance associated a default route as assigned by DHCP?
254
What is the administrative distance associated an unknown or unbelievable route?
255
A router was configured for RIP, but one of the network statements was not entered. What are symptoms of this problem?
RIP will not advertise about connected subnets matching that classful network, nor will it send or receive updates on interfaces matching that classful network. Omitting the network statement causes RIP to be disabled for those interfaces.
Router R1 was configured for RIP version 2, but the passive-interface command was configured on an interface facing router R2 by accident. What will be the result?
R2 will not receive any RIP advertisements, and thus will not learn routes from R1. However, R1 can learn routes from R2, as <passive-interface> only prevents routing updates from being sent over the interface it's applied to.</passive-interface>
When is the no auto-summary command needed?
no-autosummary only has an impact if the router is connected to more than one classful network (which implies a discontiguous classful network). It is needed only if a discontiguous classful network exists
What are some non-RIP configuration or design issues that could impact RIP operation?
- Interfaces must be working for RIP to use them (up/up)
- Routers on the same link must be in the same subnet
- ACLs may filter RIP messages, causing RIP to break
