Title: ICND2 / 2. IP Routing Technologies

Q: What is Feasible Distance?
A: The lowest cost path from the router to the destination.  This is what the router itself sees.

Q: In relation to EIGRP, what is another term for Reported Distance?
A: Advertised Distance

Q: What is Reported Distance (aka Advertised Distance)?
A: Simply put, this is OTHER (neighboring) routers feasible distance recorded in YOUR router.
This is what the neighboring routers refer to as YOUR feasible distance.  In other words, after YOU find YOUR feasible distance to the destination, you would report that to other routers.

Q: The Feasible Distance is assigned to the: _______________.
The Reported Distance comes from the: _______________.
A: Successor Route,
Next Hop Router

Q: The lowest cost route to a destination is called the _________ Route, and is placed in the routing table.
A: Successor

Q: The _________________ is a backup route or secondary route that is placed in the topology table.
A: Feasible Successor

Q: In order to be a feasible successor, the route must have a ______________ that is LESS than the ______________.
(Feasible Distance is the lowst cost path from the router to the destination.  This is what the router itself see.)
A: advertised distance,
feasible distance

Q: (EIGRP)The _______ contains everything the router knows about.
A: Topology Table

Q: The distance from YOU(router) to the destination is known as the ______________.
A: Feasible Distance

Q: The distance from the NEIGHBOR(router) to the destination is known as the ________________.
A: Reported/Advertised Distance

Q: The primary route that made its way to the routing table with the best cost to the destination is known as the __________.
A: Successor

Q: The backup route to the Successor Route is known as the __________________.
A: Feasible Successor.  This is sitting in the topology table waiting to serve as a backup in case the Successor Route goes down. When the successor route goes down, the Feasible Successor is moved into the Routing table as the Successor route and takes over.

Q: What are the requirements to become a Feasible Successor.
A: The Advertised/Reported Distance must be less than the Successor's Feasible Distance.

Q: (EIGRP)Is it good if a route is in 'Active' state?
A: No.  This means the route is down and EIGRP is trying to find a backup.

Q: (EIGRP)If a route is on a 'Passive' state, is this a good thing?
A: Yes. EIGRP is not having to take action on these routes.  They are in place, and good routes.

Q: What is the EIGRP Multicast Address for IPV4 and IPV6?
A: 224.0.0.10,
FF02::A

Q: (EIGRP)When is a query message sent?
A: When a route is lost and there is no feasible successor, a query message is sent.

Q: (EIGRP)Does the AS number have to match to be able to form a relationship?
A: Yes.

Q: (EIGRP)What happens when you type the following?:
R1(config-router)#network 10.0.0.0
A: 1. It will send hello packets out all interfaces that start with 10....
2. It will advertise any networks it has that start with 10....
It is NOT advertising "10.0.0.0"

Q: (EIGRP)How would you turn off auto-summary?
A: R2(config)#router eigrp 1
R2(config-router)#network 10.0.0.0
R2(config-router)#no auto-summary

Q: How would you see a list of your EIGRP neighbors?
A: R1#show ip eigrp neighbor

Q: In the "R1#show ip eigrp neighbor" command, what does the 'H' column repersent?
Router#show ip eigrp neigh
IP-EIGRP neighbors for process 1
H   Address         Interface      Hold Uptime    SRTT   RTO   Q   Seq
                                   (sec)          (ms)        Cnt  Num
0   10.0.0.1        Fa0/0          13   00:00:09  40     1000  0   2
A: It stands for "Handle."  It represents the order in which neighbor relationships were formed.

Q: What command would you use to see what your EIGRP hello timers are set at?
A: R1(config-if)#do show ip eigrp interfaces detail
EIGRP-IPv4 Interfaces for AS(1)
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Se0/0/0            0        0/0         0       0/1            0           0
  Hello-interval is 5, Hold-time is 15
  Split-horizon is enabled
  Next xmit serial <none>
  Un/reliable mcasts: 0/0  Un/reliable ucasts: 0/0
  Mcast exceptions: 0  CR packets: 0  ACKs suppressed: 0
  Retransmissions sent: 0  Out-of-sequence rcvd: 0
  Topology-ids on interface - 0
  Authentication mode is not set

Q: What is the default hello timer for EIGRP?
A: 5 seconds for LAN interfaces,
60 seconds for WAN interfaces

Q: What is the default hold timer for EIGRP?
A: 15 seconds

Q: When you issue the command "show ip route", what is the code for EIGRP?
A: 'D'
Router#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route
Gateway of last resort is not set
     10.0.0.0/24 is subnetted, 1 subnets
D       10.0.0.0 [90/30720] via 172.16.1.1, 00:43:36, FastEthernet0/1
     172.16.0.0/24 is subnetted, 1 subnets
C       172.16.1.0 is directly connected, FastEthernet0/1

Q: Can you use wildcard bits with EIGRP?
A: Yes.

Q: (EIGRP)What command would you use to show everything that EIGRP knows about?
A: R1#show ip eigrp topology
(Show the topology table)

Q: With the "R2#show ip eigrp topology command", what do the numbers mean in the parenthesis mean?
Router#show ip eigrp topology
IP-EIGRP Topology Table for AS 1/ID(172.16.1.2)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - Reply status
P 10.0.0.0/24, 1 successors, FD is 30720
         via 172.16.1.1 (30720/28160), FastEthernet0/1
P 172.16.1.0/24, 1 successors, FD is 28160
         via Connected, FastEthernet0/1
A: The first number (30720) is the Feasible Distance.
The second number (28160) is the Advertised Distance.

Q: When you set the bandwidth, what is it measured in?
A: Kbps

Q: How would you set the bandwidth to that of T1 speeds?
A: R1(config-if)#bandwidth 1544
(1.544Mbps)

Q: What command produced the following output?:
IP-EIGRP interfaces for process 1
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Fa0/0              1        0/0      1236       0/10           0           0
Fa0/1              1        0/0      1236       0/10           0           0
A: R1#show ip eigrp interfaces

Q: How would you summarize a route with EIGRP?
A: R1(config-if)#ip summary-address eigrp 1 172.30.0.0 255.255.248.0

Q: Whoever has the ______ specific subnet mask always makes it into the routing table. (most or least)
A: most

Q: When you auto-summarize with EIGRP, in what context do you have to do it in?
(Example: Global config, Router config, Interface config, etc)
A: Interface config.

Q: If you have a router with 2 serial interfaces and you want to auto-summarize a whole bunch of routes, do you have to summarize them out both interfaces?
A: Yes.  If you dont, only the routes with the most specific subnet masks will make it into the routing table, possibly causing unexpected results and routes to take place.

Q: How would you configure authentication for EIGRP?
A: 1. Create a Keychain
2. Create a Password in the key chain
3. Assign authentication mode/eigrp on the interface
4. Attach the key chain to the interface
R1(config)#key chain MY_CHAIN
R1(config-keychain)#key 1
R1(config-keychain-key)#key-string Password1
R1(config-keychain-key)#interface fa0/0
R1(config-if)#ip authentication mode eigrp 1 md5
R1(config-if)#ip authentication key-chain eigrp 1 MY_CHAIN
The Key numbers and string on both sides needs to be the same.

Q: What is the best practice in relation to route advertisement?
A: Make all interfaces passive interfaces:
R1(config-router)#passive-interface default
Turn off passive interfaces individually for the interfaces you want to advertise routes on:
R1(config-router)#no passive-interface se0/0
R1(config-router)#no passive-interface se0/1

Q: __________ and __________ affect the calculation of EIGRP metrics when all possible default values are used.
A: Bandwidth, delay

Q: A route’s feasible distance is the calculated metric of the _________ Route.
A: Successor

Q: What must be in place for a router to become a valid EIGRP neighbor?
A: 1. Must pass authentication if in use.
2. Must be in the same AS.
3. Must be in the same subnet.

Q: EIGRP uses _________________ to send topology information to neighbors.
A: EIGRP update messages

Q: EIGRP sends update messages with a protocol called (RTP)____________________.
A: Reliable Transport Protocol

Q: (EIGRP)Neighbors use both full routing updates and partial updates.
A full update means that a router sends information about all known routes, whereas a partial update includes only information about recently changed routes.
When does EIGRP use each of these update types?
A: Full updates when the neighbor relationship is initially formed.
Partial updates when topology changes.
(These are not hellos, but updates)

Q: (EIGRP)How would you set the delay for an interface?
A: R1(config-if)#delay 100(tens of ms)

Q: (EIGRP)Generally, a good metric strategy for networks that use EIGRP is to set the WAN bandwidth to match the ________________.
A: actual Layer 1 speed

Q: When a route fails, and the route has no feasible successor, EIGRP uses a distributed algorithm called _____ to choose a replacement route. _____ sends queries looking for a loop-free route to the subnet in question. When the new route is found, _____ adds it to the routing table.
A: Diffusing Update Algorithm (DUAL)

Q: (EIGRP)How would you set the router ID?
A: R1(config-router)#eigrp router-id 1.2.3.4

Q: (EIGRP)How would you set the hello-interval?
A: R2(config-if)#ip hello-interval eigrp <as#> <seconds>
R2(config-if)#ip hello-interval eigrp 1 5

Q: (EIGRP)How would you change the hold-time?
A: R3(config-if)#ip hold-time eigrp <AS#> <sec>
R3(config-if)#ip hold-time eigrp 1 16

Q: (EIGRP)How would you set the bandwidth on an interface?
A: R3(config-if)#bandwidth <#ofKbps>

Q: (EIGRP)How would you set the delay on an interface?
A: R1(config-if)#delay <tensofMS>

Q: (EIGRP)How would you configure support for multiple equal-cost routes?
A: R1(config-router)#maximum-paths <1-32>
or
R1(config-router)#variance <1-128>(Metric Variance Multiplier)

Q: (EIGRP)What does the variance command do?  For example:
R2(config-router)#variance 2
A: When using the variance command, eigrp will add a feasible successor to the route table if the feasible successor has a feasible distance that is less than or equal to the product of the feasible distance of the successor times the variance setting and the feasibility condition is met.

Q: What is the valid range for ASN numbers for EIGRP and process IDs for OSPF?
A: 1-65535

Q: What happens if you are using a real router, and type the following commands?:
R1(config)#router eigrp 1
R1(config-router)#network 10.1.1.0
A: The router will change 10.1.1.0 into the closest classful network (10.0.0.0) and enable EIGRP on all interfaces that start with 10.x.x.x

Q: What command produced the following output?:
EIGRP-IPv4 Interfaces for AS(1)
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Se0/0/0            1        0/0         1       0/15          50           0
Lo0                0        0/0         0       0/1            0           0
Lo1                0        0/0         0       0/1            0           0
Lo2                0        0/0         0       0/1            0           0
Lo3                0        0/0         0       0/1            0           0
A: R1#show ip eigrp interfaces

Q: What command produced the following output?:
EIGRP-IPv4 Interfaces for AS(1)
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Se0/0/0            1        0/0         1       0/15          50           0
  Hello-interval is 5, Hold-time is 15
  Split-horizon is enabled
  Next xmit serial <none>
  Un/reliable mcasts: 0/0  Un/reliable ucasts: 2/2
  Mcast exceptions: 0  CR packets: 0  ACKs suppressed: 0
  Retransmissions sent: 0  Out-of-sequence rcvd: 0
  Topology-ids on interface - 0
  Authentication mode is not set
Lo0                0        0/0         0       0/1            0           0
  Hello-interval is 5, Hold-time is 15
  Split-horizon is enabled
  Next xmit serial <none>
  Un/reliable mcasts: 0/0  Un/reliable ucasts: 0/0
  Mcast exceptions: 0  CR packets: 0  ACKs suppressed: 0
  Retransmissions sent: 0  Out-of-sequence rcvd: 0
  Topology-ids on interface - 0
  Authentication mode is not set
Lo1                0        0/0         0       0/1            0           0
  Hello-interval is 5, Hold-time is 15
 --More--
...
A: R1#show ip eigrp interfaces detail

Q: What command produced the following output?:
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 1"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP-IPv4 Protocol for AS(1)
    Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
    NSF-aware route hold timer is 240
    Router-ID: 192.168.1.1
    Topology : 0 (base)
      Active Timer: 3 min
      Distance: internal 90 external 170
      Maximum path: 4
      Maximum hopcount 100
      Maximum metric variance 1
  Automatic Summarization: disabled
  Maximum path: 4
  Routing for Networks:
    10.0.0.0/24
    10.0.1.0/24
    10.0.2.0/24
    10.0.3.0/24
    172.16.0.0/24
  Routing Information Sources:
    Gateway         Distance      Last Update
  Distance: internal 90 external 170
A: R1#show ip protocols

Q: What command produced the following output?:
EIGRP-IPv4 Topology Table for AS(1)/ID(192.168.1.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status
P 10.0.3.0/24, 1 successors, FD is 128256
        via Connected, Loopback3
P 10.0.1.0/24, 1 successors, FD is 128256
        via Connected, Loopback1
P 172.16.0.0/24, 1 successors, FD is 2169856
        via Connected, Serial0/0/0
P 10.0.0.0/24, 1 successors, FD is 128256
        via Connected, Loopback0
P 10.0.2.0/24, 1 successors, FD is 128256
        via Connected, Loopback2
A: R1#show ip eigrp topology

Q: What command produced the following output?:
Gateway of last resort is not set
      10.0.0.0/24 is subnetted, 4 subnets
D        10.0.0.0 [90/2297856] via 172.16.0.1, 00:08:38, Serial0/1/0
D        10.0.1.0 [90/2297856] via 172.16.0.1, 00:08:38, Serial0/1/0
D        10.0.2.0 [90/2297856] via 172.16.0.1, 00:08:38, Serial0/1/0
D        10.0.3.0 [90/2297856] via 172.16.0.1, 00:08:38, Serial0/1/0
A: R2#show ip route eigrp

Q: How would you check the routing table for only EIGRP related routes?
A: R3#show ip route eigrp

Q: (EIGRP)If an interface is set to be passive (passive-interface se0/1/0), will it show up in the output of the following command?:
R1#:show ip eigrp interfaces
A: No.

Q: If you are trying to search for EIGRP enabled interfaces, where is a good place to start?
A: R1#show ip eigrp interfaces
next would be
R1#show ip protocols

Q: Can you see the Router-ID using the "show ip protocols" command?
A: Yes:
R1#show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 1"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP-IPv4 Protocol for AS(1)
    Metric weight K1=1, K2=0, K3=1, K4=0, K5=0
    NSF-aware route hold timer is 240
    Router-ID: 192.168.2.1 <--------------------------------------------
    Topology : 0 (base)
      Active Timer: 3 min
      Distance: internal 90 external 170
      Maximum path: 4
      Maximum hopcount 100
      Maximum metric variance 1

Q: Is the configuration of the RID different between OSPF and EIGRP?
A: Yes.
OSPF: R1#(config-router)eigrp router-id 1.2.3.4
EIGRP: R1#(config-router)router-id 1.2.3.4

Q: When does IOS use administrative distance?
A: IOS uses the administrative distance to choose the better route when IOS learns multiple routes to the same subnet but from two different sources of routing information.

Q: What command would you use to see only a certain subnet of the topology table?
A: R1#show ip eigrp topology | section 10.1.1.0

Q: Which route is the Successor Route?
Which route is the Feasible Successor?
What number is the Feasible Distance?
What number is the Reported Distance?
R1# show ip eigrp topology | section 10.1.33.0
P 10.1.33.0/24, 1 successors, FD is 2684416
via 10.1.4.3 (2684416/2172416), Serial0/0/1
via 10.1.5.2 (2854912/2342912), Serial0/0/0
A: Successor Route is through 10.1.4.3
Feasible Successor is thrhough 10.1.5.2
Feasible Distance is 2,684,416
Reported Distance of Feasible Successor is 2,342,912

Q: Fill in the labels:
A: 1. Number of Successors
2. Feasible Distance
3. Successor Route
4. Feasible Successor
5. Reported Distance (of Feasible Successor)

Q: What is the point of having a Feasible Successor Route?
A: Quicker convergence time since EIGRP won't need to send query messages.

Q: What command produced the following output?:
IP-EIGRP (AS 1): Topology entry for 172.16.0.0/16
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 156160
  Routing Descriptor Blocks:
  192.168.0.2 (FastEthernet0/0), from 192.168.0.2, Send flag is 0x0
      Composite metric is (156160/128256), Route is Internal
      Vector metric:
        Minimum bandwidth is 100000 Kbit
        Total delay is 5100 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 1
A: Router#show ip eigrp topology 172.16.0.0

Q: (EIGRP)The variance multiplier EIGRP router subcommand defines an integer between ___ and ___.
A: 1, 128

Q: (EIGRP)When using un-equal cost load balancing, what are the requirements for a route to be added to the routing table.
A: FS Route Metric must be <= (FD * Variance)
The route in question MUST be a Feasible Successor eligible or it won't be added to the routing table, even if the FS Route Metric is less than FD * Variance

Q: Why does Cisco recommend that if you want to tune EIGRP metrics, change the interface delay settings as opposed to bandwidth?
A: Because fewer other IOS features rely on the interface delay setting.

Q: How would you see the bandwidth and delay that you set on an interface?
A: Router#show interfaces eth0/0/0
Ethernet0/0/0 is up, line protocol is up (connected)
  Hardware is Lance, address is 0030.a37a.001a (bia 0030.a37a.001a)
  Internet address is 10.0.2.1/24
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,  <-----------------------------
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  ARP type: ARPA, ARP Timeout 04:00:00,
  Last input 00:00:08, output 00:00:05, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: fifo
  Output queue :0/40 (size/max)
  5 minute input rate 114 bits/sec, 0 packets/sec
  5 minute output rate 102 bits/sec, 0 packets/sec
     577 packets input, 35012 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 input packets with dribble condition detected
     488 packets output, 29217 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

Q: What command produced the following output?:
IP-EIGRP interfaces for process 1
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Eth0/0/0           1        0/0      1236       0/10           0           0
Eth0/1/0           1        0/0      1236       0/10           0           0
Fa0/1              1        0/0      1236       0/10           0           0
Fa0/0              1        0/0      1236       0/10           0           0
A: Router#show ip eigrp interfaces

Q: How could I debug to see changes to the EIGRP Successor and Feasible Successor routes?
A: R1#debug eigrp fsm

Q: (OSPF)Do all routers in the same area have the same LSDB?
A: Yes.

Q: Does single area OSPF support summarization?
A: No.

Q: (OSPF)What is the point of having multiple area?
A: Route Summarization and Fault Containment

Q: (OSPF)What is an area border router?
A: A router running OSPF that has interfaces in more than one area.

Q: (OSPF)Do ABRs NEED to summarize?
A: No. But there will be no fault containment between the areas. There is no point to NOT summarize routes on the ABR.

Q: (OSPF)Is fault containment drastically dependent on route summarization?
A: Yes.

Q: (OSPF)What is an Autonomous System Boundary Router (ASBR)?
A: It's a router that connects you to networks outside of your own.
Could be the Internet, RIP, a different EIGRP network

Q: (OSPF)____________ and ____________ are the ONLY routers that can summarize.
A: Area Border Routers
Autonomous System Boundary Routers

Q: (OSPF)Area ___ is the first area you create and is considered the backbone.
A: 0

Q: (OSPF)All areas that you create have to be connected to _________.
A: Area 0, the backbone

Q: What are the default Hello timers for OSPF?
A: Once every 10 seconds on Broadcast and P2P Networks
Once every 30 seconds on Non-broadcast multi-access network (NBMA, Frame-Relay network)

Q: What is the default OSPF Dead/Holddown timer?
A: 40 seconds

Q: What is the point of the DR/BDR concept?
A: If you have 10 Routers connected to the same switch and a link goes down, If there is no designated router, because all the routers have formed full neighbor relationships with eachother, they will spam eachother when a link goes down or the topology changes creating a lot of unnecessary traffic.
However if there is a DR in place, the router who owns the link that went down will report it to the DR and BDR.  The DR will then tell everyone else about the topology change.

Q: (OSPF)What happens if two routers parameters are not compatible with one another?
A: They will show up in the neighbor table periodically with the state of 'Init' and will never form a relationship.

Q: (OSPF)How is it determined who sends their routes first? (Master Slave Relationship)
A: Highest priority breaks the tie, whoever has the highest Router-ID

Q: (OSPF)What is a Database Description (DBD) packet?
A: This is the cliff-notes or a summary of what is in the Link State Data Base (LSDB).

Q: How are Database Descriptions acknowledged and reviewed?
A: Slave requests details in a 'Link State Request' (LSR)
Master sends updates in a 'Link State Update' (LSU)
Master requests details in a 'Link State Request' (LSR)
Slave sends updates in a 'Link State Update' (LSU)

Q: (OSPF)How are neighbors formed (in detail)
A: R1 Sends hello
R2 Sends hello
R1(Master) sends DB Description/Summary of LSDB
R2(Slave) receives it and sends his DBD
[They review eachothers DBDs]
R2(Slave) LSR requests full info on previously unknown routes
R1(Master) LSU sends updates to R2
[They continue to send eachother LSRs and LSUs until they reach the "FULL" neighbor state

Q: (OSPF)What are the states that OSPF goes through before a full neighbor relationship is formed?
A: DOWN
INIT (hellos sent)
2WAY (After they realize they are compatible/parameters)
EXSTART (choosing Master/Slave relatinoship)
EXCHANGE (sending DBDs back and forth)
LOADING (loading individual LSUs)
FULL (full neighbor relationship)]]]

Q: Should you configure Bandwidth on serial interfaces?
A: Yes.  The bandwidth is used to calculate cost in OSPF as well as calculations for EIGRP.
R1(config-if)#bandwidth 1544 (Kbps)

Q: How does the SPF algorithm calculate cost?
A: 100/bandwidth (in Mbps)

Q: (OSPF)Why would you have to adjust the cost formula?
A: Because when you start getting to FastEthernet and Gigabit Ethernet, they will all have the same cost
100/100 = cost of 1
100/1000 = cost of 1
100/10000 = cost of 1
The router won't be able to tell the difference between these interfaces.

Q: Why would you create a loopback address the same as the Router-ID and then advertise that with OSPF?
A: In order to ping the router by the Router-ID from a remote network.

Q: What does IA mean in the routing table?
A: Inter Area, this shows up when a route goes through an ABR.

Q: (OSPF)If you create an ABR by adding two interfaces on your router to two separate OSPF areas, what else must you do?
A: You must do route summarization, or there is literally no point in having an ABR.

Q: The more specific the subnet mask is, the _____ the route.
A: better

Q: (OSPF)How might you summarize the following networks who live in area 20 on an ABR?
10.20.3.0/24
10.20.4.0/24
10.20.5.0/24
10.20.6.0/24
A: R3(config-router)#area 20 range 10.20.0.0 255.255.0.0

Q: (OSPF)What is included inside of an LSU?
A: One or more LSAs

Q: (OSPF)How would you revert the hello timer back to default?
A: R1(config-if)#no ip ospf hello-interval

Q: What does the following output mean?:
*Mar 1 00:40:30.339: OSPF: Mismatched hello parameters from 10.1.1.2
*Mar 1 00:40:30.339: OSPF: Dead R 40 C20, Hello R 10 C 5
A: There is a timer mismatch preventing an OSPF neigh relationship from forming.
Remote Dead: 40 seconds
Local Dead: 20 seconds
Remote Hello: 10 seconds
Local Dead: 5 seconds

Q: When does OSPF choose it's RID?
A: When OSPF is first initialized.  If you change the RID, you must time clear ip ospf process to re-initialize.

Q: What happens if OSPF cannot find a valid RID?
A: OSPF will not work.

Q: (OSPF)What phase of the neighbor relationship formation occurs when R1 is aware of R2, but R2 is not aware of R1.
A: Init. R1 lists R2 as a neighbor, with an interim state of "Init"

Q: (OSPF)What state in the neighbor establishment process is when R1 sends the initial Hello to R2, and R2 sends its initial hello back to R1?
A: At this point R1 and R2 have both moved into the "2-way state" phase.

Q: (OSPF)Once two routers have reached the "2-way state" in the neighbor relationship process, what can you assume to have happened?
A: 1. The router received a Hello from that neighbor, with that router's own RID listed as being [seen] by the neighbor.
2. The router has checked all the parameters in the Hello received from the neighbor and discovered no problems.  The router is willing to become a neighbor.

Q: (OSPF)Once the two neighboring routers on a point-to-point link reach a 2-way state, it means they are available to begin a 2-way exchange of the _________.
A: LSDB

Q: What is an LSA?
A: A Link-State Advertisement is the name of a data structure that resides inside the LSDB and describes in detail the various components in a network, including routers and links (subnets).

Q: What is an LSDB?
A: In OSPF, The Link-State Database is the data structure in RAM of a router that holds the various LSAs, with the collective LSAs representing the entire topology of the network.

Q: (OSPF)After routers enter the 2-way state, what do they do next?
A: They tell each other a list of LSAs in their respective databases--not all the details of the LSAs, just a list. (Think of these lists as checklists.) Then, each router can check which LSAs it already has, and then ask the other router for only the LSAs that are not known yet.

Q: The OSPF messages that actually send the LSAs between neighbors are called ________________________ packets.
A: Link-State Update (LSU)

Q: When OSPF has fully converged, what happens if a topology change occurs?
A: When something changes, one or more routers change one or more LSAs. Then, the routers must flood the changed LSAs to each neighbor so that the neighbor can update its LSDB

Q: What happens after the network topology changes and new LSAs have been flooded to all routers in the area?
A: Each router will have to use the SPF algorithm to recalculate any routes affected by the topology change.

Q: Does OSPF perform any passive maintenance tasks?
A: Yes.  OSPF will reflood each LSA occasionally, even when the network is completely stable. By default, each router that creates an LSA also has the responsibility to reflood the LSA every 30 minutes (the default), even if no changes occur. (Note that each LSA has a separate timer, based on when the LSA was created, so there is no single big event where the network is overloaded with flooding LSAs.)

Q: (OSPF)If you have five routers connected to a switch all on the same subnet, can they all form full neighbor states with eachother?
A: Because the DR and BDR both do full database exchange with all the other OSPF routers in the LAN, they reach a full state with all neighbors. However, routers that are neither a DR nor a BDR—called DROthers by OSPF—never reach a full state because they do not do database exchange with each other. As a result, the show ip ospf neighbor command on these routers list some neighbors, permanently, in a state of 2-way, and not in a full state.
R4#show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
192.168.0.1       1   FULL/BDR        00:00:33    192.168.0.1     FastEthernet0/0
192.168.0.2       1   2WAY/DROTHER    00:00:31    192.168.0.2     FastEthernet0/0
192.168.0.3       1   2WAY/DROTHER    00:00:38    192.168.0.3     FastEthernet0/0
192.168.0.6       1   FULL/DR         00:00:32    192.168.0.6     FastEthernet0/0

Q: (OSPF)What does adjacent mean?
A: In OSPF, a characterization of the state of a neighbor in which the two neighbors have reached the full state.
In 2-way adjacency (on a LAN), the neighbor has sent a Hello that lists the local router's RID in the list of seen routers, also implying that neighbor verification checks all passed. If both neighbors are DROther routers, the neighbors should remain in this state.

Q: (OSPF)What does it mean to be fully adjacent?
A: Both routers know the exact same LSDB details and are fully adjacent, meaning they have completed the exchange of LSDB contents.

Q: (OSPF)What is a Backbone Router?
A: A router in one area (the backbone area).

Q: What is an Internal Router?
A: A router in one area (not the backbone area)

Q: (OSPF)What is an Intra-Area Route?
A: A route to a subnet inside the same area as the router.

Q: What is an Inter-Area Route?
A: A route to a subnet in an area of which the router is not a part.

Q: (OSPF)What is a router LSA?
A: A type of LSA that a router creates to describe itself.

Q: (OSPF)What is a Network LSA?
A: This is a type of LSA that a designated router (DR) creates for the network (subnet) for which the DR is helping to distribute LSAs.

Q: (OSPF)What is a Summary LSA?
A: A type of LSA created by the ABR to describe a subnet in one area in the database of another area.

Q: What is LSA type #1
A: Router LSA, Describes:
RID
IP Addresses
Subnet IDs
Masks

Q: What is LSA type #2
A: Network, Describes network that has a DR:
DR and BDR IP Addresses,
Subnet ID,
Mask

Q: What is LSA type #3
A: Describe a Subnet in another area,
Subnet ID,
Mask,
RID of ABR that advertises the LSA

Q: What are Type 4 and Type 5 LSAs?
A: In some networks, both OSPF and other routing protocols are used. In that case, one or more routers run both OSPF and the other routing protocol, with those routers acting as an OSPF Autonomous System Border Router, or ASBR, redistributing routing information between OSPF and the other protocol. In such a case, the ASBR creates a Type 4 LSA, which describes the ASBR itself itself, and Type 5 LSAs for each external route learned from the other routing protocol and then advertised into OSPF.

Q: (OSPF)What is contained within a router LSA?
A: 1. Router's RID as the LSA Identifier
2. Interface
3. IP Addresse
4. Subnet Mask
5. Pointers to neighbors

Q: Which LSDBs do Area Border Routers have a copy of?
A: ABRs have a copy of the LSDB for each Area in which they connect?

Q: What command produced the following output?:
            OSPF Router with ID (192.168.0.2) (Process ID 1)
                Router Link States (Area 0)
Link ID         ADV Router      Age         Seq#       Checksum Link count
192.168.0.1     192.168.0.1     615         0x80000002 0x00747D 2
192.168.0.2     192.168.0.2     498         0x80000006 0x00F482 3
                Summary Net Link States (Area 0)
Link ID         ADV Router      Age         Seq#       Checksum
2.2.2.2         192.168.0.1     454         0x80000001 0x00C2F6
3.3.3.3         192.168.0.1     423         0x80000001 0x009421
4.4.4.4         192.168.0.1     8           0x80000001 0x00664B
5.4.3.0         192.168.0.1     18          0x80000001 0x007049
10.0.0.0        192.168.0.1     600         0x80000001 0x00803B
99.99.99.99     192.168.0.1     278         0x80000001 0x0043F0
172.16.0.0      192.168.0.1     610         0x80000001 0x007D8B
A: R1#show ip ospf database

Q: On the ABR, how would you easily check which area certain networks are in?
A: ABR#show ip protocols
Routing Protocol is "ospf 1"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Router ID 192.168.0.1
  It is an area border router
  Number of areas in this router is 4. 4 normal 0 stub 0 nssa
  Maximum path: 4
  Routing for Networks:
    5.4.3.0 0.0.0.3 area 3
    10.0.0.0 0.0.0.3 area 2
    172.16.0.0 0.0.0.3 area 1
    192.168.0.0 0.0.0.3 area 0
 Reference bandwidth unit is 100 mbps
  Routing Information Sources:
    Gateway         Distance      Last Update
    5.4.3.2              110      00:14:07
    10.0.0.2             110      00:21:02
    192.168.0.2          110      00:22:13
    172.16.0.2           110      00:18:37
  Distance: (default is 110)

Q: On the ABR, how would you see a list of all interfaces running OSPF and the area they are operating in?
A: ABR#show ip ospf interface brief
Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C
Se1/0        1     0               192.168.0.1/30     781   P2P   1/1
Se1/1        1     1               172.16.0.1/30      781   P2P   1/1
Se1/2        1     2               10.0.0.1/30        781   P2P   1/1
Se1/3        1     3               5.4.3.1/30         781   P2P   1/1

Q: Other than "show ip ospf neighbor", how else can I see who the DR and BDR are?
A: R4# show ip ospf interface gigabitEthernet 0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 10.1.14.4/24, Area 4, Attached via Network Statement
Process ID 1, Router ID 10.1.14.4, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 10.1.14.4, Interface address 10.1.14.4 <------------
Backup Designated router (ID) 1.1.1.1, Interface address 10.1.14.1 <------------

Q: When you issue the following command, what will the bandwidth for the interface be set to?:
ABR(config-if)#bandwidth 64
A: 64Kbps

Q: When calculating Cost, how does OSPF round numbers?
A: It truncates the decimal (rounds down).

Q: (OSPF)How would you explicitly set the cost for an interface?
A: R1(config-if)#ip ospf cost x (1-65535)

Q: (OSPF)How would you load balance?
A: When two routes have the same cost to the same location, you can issue the following command in the ospf router config:
ABR(config-rtr)#maximum-paths [1-16]

Q: Which Enhanced Interior Gateway Routing Protocol (EIGRP) packet is NOT sent reliably over the network?
A: Acknowledgement packets are sent unreliably over the network, and there is no guaranteed delivery of acknowledgement packets between neighboring routers.
Acknowledgement packets are a special type of hello packets that do not contain data and have a non-zero acknowledgement number. These are sent as a unicast.
Update, Query, and Reply packets use Reliable Transport Protocol (RTP), which ensures guaranteed delivery of packets between neighboring devices. The RTP mechanism ensures loop-free synchronized network.

Q: For an interface to be considered in OSPF DR selection, does OSPF need to be advertised on that interface?
A: Yes.

Q: What command produced the following output?:
IP-EIGRP Traffic Statistics for AS 1
  Hellos sent/received: 76/62
  Updates sent/received: 12/8
  Queries sent/received: 0/0
  Replies sent/received: 0/0
  Acks sent/received: 5/9
  Input queue high water mark 1, 0 drops
  SIA-Queries sent/received: 0/0
  SIA-Replies sent/received: 0/0
  Hello Process ID: 120
  PDM Process ID: 119
A: FR_SWITCH#show ip eigrp traffic

Q: Which command is used to view the number of EIGRP packets that are sent and received?
A: R1#show ip eigrp traffic
EIGRP-IPv4 Traffic Statistics for AS(1)
  Hellos sent/received: 90/90
  Updates sent/received: 3/5
  Queries sent/received: 0/0
  Replies sent/received: 0/0
  Acks sent/received: 4/2
  SIA-Queries sent/received: 0/0
  SIA-Replies sent/received: 0/0
  Hello Process ID: 209
  PDM Process ID: 130
  Socket Queue: 0/2000/1/0 (current/max/highest/drops)
  Input Queue: 0/2000/1/0 (current/max/highest/drops)

Q: What command produced the following output?:
 Routing Process "ospf 1" with ID 192.168.0.2
 Start time: 00:02:11.548, Time elapsed: 00:01:07.320
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Supports Link-local Signaling (LLS)
 Supports area transit capability
 Supports NSSA (compatible with RFC 1587)
 Event-log enabled, Maximum number of events: 1000, Mode: cyclic
 Router is not originating router-LSAs with maximum metric
 Initial SPF schedule delay 5000 msecs
 Minimum hold time between two consecutive SPFs 10000 msecs
 Maximum wait time between two consecutive SPFs 10000 msecs
 Incremental-SPF disabled
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 Number of external LSA 0. Checksum Sum 0x000000
 Number of opaque AS LSA 0. Checksum Sum 0x000000
 Number of DCbitless external and opaque AS LSA 0
 Number of DoNotAge external and opaque AS LSA 0
 Number of areas in this router is 1. 1 normal 0 stub 0 nssa
 Number of areas transit capable is 0
 External flood list length 0
 IETF NSF helper support enabled
 Cisco NSF helper support enabled
 Reference bandwidth unit is 100 mbps
    Area BACKBONE(0)
        Number of interfaces in this area is 2 (1 loopback)
        Area has no authentication
        SPF algorithm last executed 00:00:26.376 ago
        SPF algorithm executed 2 times
        Area ranges are
        Number of LSA 2. Checksum Sum 0x010DD4
        Number of opaque link LSA 0. Checksum Sum 0x000000
        Number of DCbitless LSA 0
        Number of indication LSA 0
        Number of DoNotAge LSA 0
        Flood list length 0
A: R1#show ip ospf

Q: What command produced the following output?:
OSPF statistics:
  Last clearing of OSPF traffic counters never
  Rcvd: 18 total, 0 checksum errors
        11 hello, 3 database desc, 0 link state req
        2 link state updates, 2 link state acks
  Sent: 20 total
        12 hello, 4 database desc, 1 link state req
        2 link state updates, 1 link state acks
            OSPF Router with ID (192.168.0.2) (Process ID 1)
OSPF queue statistics for process ID 1:
                   InputQ     UpdateQ    OutputQ
  Limit            0          200        0
  Drops            0          0          0
  Max delay [msec] 4          0          0
  Max size         1          1          2
    Invalid        0          0          0
A: R1#show ip ospf traffic

Q: Is IGRP a classless routing protocol?
A: No, IGRP is classful. Classless routing protocols support variable length subnet masks (VLSM), which allow different subnets of a given IP network to be configured with different subnet masks.

Q: What is the metric size EIGRP uses?
A: 32-bits

Q: What is the default Administrative Distance (AD) value for an Enhanced Interior Gateway Routing Protocol (EIGRP) summary route?
A: 5

Q: On which type of networks will OSPF selected a DR/BDR?
A: Broadcast Network (All connected to a switch)
NBMA (Frame relay)

Q: (OSPF)The Pri field indicates the priority of the neighbor router. The router with the _________ priority becomes the designated router (DR). If the priorities are the same, then the router with the _________ router ID becomes the DR. By default, priorities are set to 1. A router with a priority of ___ never becomes a DR or a backup designated router (BDR); it is always a DROTHER, meaning a router that is neither the DR or the BDR.
A: highest,
highest,
0

Q: What is the default interface configuration used by Open Shortest Path First (OSPF) to run over Frame Relay?
A: By default, OSPF uses Non-Broadcast Multi-Access mode (also written as nonbroadcast multiaccess) when running over Frame Relay. There are three possible modes available when configuring OSPF over Frame Relay links: two for physical interfaces and one for subinterfaces.