Routing Protocols Flashcards
RIP metric, classful or classless, how advertised, and AD
Hop count, Distance vector, v1 classful/v2 classless, 120
IGRP metric, classful or classless, how advertised, and AD
Bandwidth and Delay, classful, Distance vector, 100
EIGRP metric, classful or classless, how advertised, and AD
Bw and delay, classless, hybrid, 90 or 170
OSPF metric, classful or classless, how advertised, and AD
Link state, classless, cost bw, 110
IS-IS metric, classful or classless, how advertised, and AD
Link state, classless, cost 10, 115
BGP metric, classful or classless, how advertised, and AD
Path vector, classless, many path attrib, 20 and 200
Interior gatway protocol examples
EIGRP, IS-IS (ISP typically), OSPF, RIP
External gateway protocol examples
BGP
Distance vector protocol examples
EIGRP and RIPv2
Link-State Protocol examples
OSPF and IS-IS
Exchanges info about the whole topology. Each router determines the best paths on its own, using SPF.
Link-state protocols
Exchanges routes as vectors of distance and direction. Distance=metric of links or hop count, Direction=next-hop neighbor
Distance vector protocols
Exchanges routes as the vector of path and direction. Path = list of different path attributes, Direction=next-hop neighbor
Path vector protocols
Address assigned to an interface on more than 1 node. When packet is sent, it is routed to the nearest interface that has the address.
Anycast
Local broadcast address
255.255.255.255
Last IP address in the subnet
Directed broadcast address
224.0.0.0 to 239.255.255.255
Reserved ipv4 multicast address
224.0.0.5 and 224.0.0.6
Multicast OSPFv2
224.0.0.9
RIPv2 multicast
224.0.0.10
EIGRP multicast
FF02:5 and FF02:6
Multicast OSPFv3
FF02:9
RIPng multicast
FF02:A
EIGRP multicast
2000::/3
Global IPv6 addresses
FE80::/10
Link-local addresses
FF00::/8
Multicast addresses
FC00:7
Unique local addresses
::1
Loopback
Example of a broadcast network
Ethernet
A network that can support many routers but does not have broadcast ability
NBMA network (e.g. Frame relay and ATM)
Point-to-Point technology that allows the transport of any layer 2 protocol at the PE
VPWS (Virtual private wire service)
Emulates an Ethernet multiaccess LAN segment over the MPLS core and provides multipoint-to-multipoint service
VPLS (Virtual private lan service)
3 main components of a GRE tunnel
(1) Passenger protocol (IPv4, IPv6)
(2) Carrier Protocol (GRE)
(3) Transport Protocol (IP)
GRE creates this many bytes of additional overhead
24
This technology enables a single GRE interface to support multiple GRE tunnels and simplifies the complexity of the configuration.
mGRE
DMPVPN relies on what 3 things
mGRE, NHRP, IPsec
Routing protocol: If a network is 16 or more hops away, the router considers it unreachable.
RIP
udp port 520
RIP IPv4
udp port 521
RIP IPv6
Routing protocol: Subnet mask is not exchanged during the update process.
RIPv1
AD of RIP
120
Routing updates every 30 seconds and with topology change
RIP
Operates within an autonomous system
IGP
Operates between autonomous systems
EGP
Each router determines the best path on its own
distance vector protocol
Exchanges only the best routes with its neighbors
Link-state protocol
3 Benefits of route summarization: A. smaller routing table B. lower use of IP addresses C. more accurate path selection D. fewer routing updates E. Improved convergence
ADE
Which one of these four RIPng configuration steps can you leave out but still have RIPng up and running at the end? A. enable IPv6 routing B. create a RIPng routing process C. enable IPv6 on the interface D. enable RIPng on the interface
B
EIGRP protocol number
88
Metric calculation for EIGRP
Advertised metric + link cost
EIGRP packets
Hello, ACK, Update,
Routing protocol: Uses RTP for reliable, guaranteed delivery of packets.
EIGRP
Uses DUAL (Diffusing Update Algorithm) to calculate the best routes to remote networks.
EIGRP
T/F: Metric is not used for the EIGRP metric calculation. except in tie-breaker cases.
True, but MTU is exchanged in routing updates.
EIGRP: Another word for metric weights
K-Value..default is 0
The EIGRP delay value is the sum of the delays in the math, in _______, while the show interface output displays the delay in ______.
tens of microseconds/microseconds
_____ means that reported distance must be less than feasible distance and is critical to maintain loop-free topology.
Feasibility condition
Routers configured as ____ do not forward EIGRP learned routes to other neighbors.
Stubs
EIGRP: Without a feasible successor, ,when successor goes down, a ____ must be sent.
Query
Nonstub routers will/will not send query messages to stub routers?
will not
Command to change a router to stub for EIGRP
router eigrp 1
eigrp stub
If a router does not receive a reply to all the outstanding EIGRP queries within three minutes (the default time), the route goes into the ____ state
SIA
EIGRP: Once the ____ timer expires, the neighbor relationship is reset.
active
EIGRP: If the router receives enough packets to maintain the neighbor relationship, but is not receiving all the queries or replies, the affected devices will generate what error messages?
EIGRP DUAL-3-SIA error messages
When no reply to a query is received, EIGRP sends a ____ packet when the active timer is halfway through, after 90 seconds.
SIA-Query
EIGRP summarization limits ______ and improves ______
query scope/convergence
Command for manual summarization EIGRP
ip summary-address eigrp
Default value for EIGRP variance? Max value?
1 (default) / 128 (max)
The only way to summarize IPv6-advertised prefixes in EIGRP is ____
manual summarization
EIGRP: If you don’t assign a router ID, what happens?
the router will automatically assign it the highest loopback or the highest active interface IPv4 address. IPv6 requires a router ID.
EIGRP for IPv6 uses assigned dedicated multicast address what? how about IPv4?
FF02::A / 224.0.0.10
____ EIGRP configuration tries to eliminate configuration complexity that occurs when configuring EIGRP for both IPv4 and IPv6.
Named
Within the EIGRP address family, what is the command to enter address family interface configuration mode?
af-interface
What is the formula for selecting a feasible successor?
A. The AD of the current successor route is less than the FD of the feasible successor route.
B. The FD of the current successor route is less than the AD of the feasible successor route.
C. The FD of the feasible successor route is less than the AD of the current successor route.
D. The AD of the feasible successor route is less than the FD of the current successor route.
D
What does the passive state in the EIGRP topology table signify?
A. There are outstanding queries for this network.
B. The network is unreachable.
C. The network is up and operational, and conditions are normal.
D. A feasible successor has been selected.
C
____ propagates link-state advertisements rather than routing table updates.
OSPF
Requirements for an OSPF neighbor to establish. (4)
- Area has to match
- Hello/Dead timers have to match
- Stub flag must match
- Authentication must match
OSPF: discovers neighbors and builds adjacencies between them.
Hello
OSPF: Checks for database synchronization between routers. Packet describes the LSDB.
DBD
OSPF: Requests specific LSAs from another router that are missing in its table.
LSR(equest)
OSPF: Sends specifically requested LSAs. Are the flooded responses from LSR packets.
LSU(pdate)
To calculate the best path, OSPF uses ___ or ____
SPF or Dijkstra’s algorithm
OSPF protocol number
89
T/F: OSPF uses broadcast, rather than multicast or unicast
F. OSPF uses multicast or unicast
OSPF multicast address
224.0.0.5 for OSPF routers and 224.0.0.6 for DR and BDR routers
T/F: OSPF can do auto summarization.
F: OSPF does manual only.
What authentication for OSPF?
cleartext, MD5, and SHA
OSPF area 0 is also known as ___
backbone area or transit area
OSPF: end users are not found within ____
backbone area/area 0
OSPF: A backbone area connects to all other ___.
nonbackbone areas
A router that has interfaces connected to at least 2 different OSPF areas, including the backbone area.
ABR
A router that has at least one of its interfaces connected to an OSPF area and at least one of its interfaces connected to an external non-OSPF domain.
ASBR