Cisco BSCN Edition 1

8/9/2019 Cisco BSCN Edition 1

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CCNP

STUDY GUIDE

Building Scalable

Cisco Networks (BSCN)

640-503Edition 1


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Using EIGRP in a Scalable Network ...................................................................................... 7

BGP ................................................................................................................................................. 8

Configuring Basic Border Gateway Protocol.............................................................................. 8BGP Use.................................................................................................................................. 8

When to use BGP .................................................................................................................... 8

When not to use BGP.............................................................................................................. 8BGP Peers or Neighbors ......................................................................................................... 8

Policy-Based Routing.............................................................................................................. 8

Well Known Attributes ........................................................................................................... 8

Optional Attributes.................................................................................................................. 9Defined BGP Attributes .......................................................................................................... 9

BGP Synchronization.............................................................................................................. 9

BGP Message Types ............................................................................................................... 9Implementing BGP in Scalable Networks ................................................................................ 10

Route Reflectors.................................................................................................................... 10

Policy Control and Prefix Lists ............................................................................................. 10

Optimizing Routing Update Operation ......................................................................................... 10What is redistribution? .............................................................................................................. 10

Policy-based Routing ................................................................................................................ 10


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1

Key Concepts

Building Scalable Cisco Networks (BSCN)

Routing Principles

Routing is a relay process in which items are forwarded from one location to another. Themechanism of learning and maintaining awareness of the network topology is considered to be

the routing function.

Routing Metric

In a routed network the routing process relies on the routing protocol to maintain a loop-free to-

pology and to locate the best path to every destination network.

RIP Routing Metrics

RIP is a commonly used routing protocol in small to medium sized TCP/IP networks.

IGRP Routing Metrics

Ciscos IGRP is a commonly used routing protocol in medium to large sized TCP/IP networks.

IGRP uses a composite metric, based upon bandwidth, delay, reliability, load, and maximumtransmission unit (MTU).

Classful RoutesClassful routing protocols, such as RIPv1 and IGRP, exchange routes to subnetworks within the

same major Class (A, B or C) network. Classful routing is the result of subnet masks not being

included in the routing advertisements generated by most distance vector routing protocols.

Classless Routing

Classless routing protocols can be considered second-generation protocols because they are de-

signed to deal with some of the limitations of the earlier classful protocols.

Distance Vector Operation

The periodic routine routing updates generated by most distance vector routing protocols go onlyto directly connected routing devices.

Convergence

In a routed network, the routing process in each router must maintain a loop-free single path toeach possible destination logical network. When all the routing tables are synchronized and each

contains a usable route to each destination network, the network is converged.

EIGRP Convergence

A router running EIGRP uses reliable multicast messages when it sends queries and updates to

other routers.


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OSPF Convergence

A router running OSPF uses a multicast address to propagate LSAs. LSA is state information

about a link or a network.

IP Addresses

Current challenges in IP Addressing

An IP address consists of a 32-bit number with two components: a network address and a node.The incredible growth of the Internet has resulted in following challenges:

IP address exhaustion Routing table growth and manageability

IP Addressing Solutions

Solutions have been developed to slow the depletion of IP addresses and to reduce the number of

Internet route table entries by enabling more hierarchical layers in an IP address. These solutions

include the following:

Subnet masking Address allocation for private internets Network Address Translation (NAT) Hierarchical addressing Variable-length subnet masks (VLSMs) Route summarization Classless Interdomain Routing (CIDR)

Hierarchical Addressing

The benefits of hierarchical addressing are:

Reduced number of routing table entries Efficient allocation of addresses

Variable Length Subnet Masks

The VLSMs are commonly used to maximize the number of possible addresses available for anetwork. The benefits if VLSMs are:

Even more efficient use of IP addresses

Greater capability to use route summarization

Route Summarization

Route summarization can reduce the number of routes that a router must maintain because it is a

method of representing a series of network numbers in a single summary address.


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Cisco routers manage route summarization in two ways:

Sending route summaries Selecting routes from route summaries

CIDRCIDR is a mechanism developed to help alleviate the problem of exhaustion of IP addresses and

growth of routing tables.

Redistribution Implementation Guidelines

Be familiar with your network and your network traffic Do not overlap routing protocols One-way redistribution Two-way redistribution

NATNetwork Address Translation can be used to merge two large networks without having to re-

address the whole network. Another function of NAT is overloading inside global addresses.

This process allows several inside addresses to use a single IP address. NAT can also use a poolof addresses or multiple interfaces.

Using IP Unnumbered Serial Interface

To enable IP processing on a serial interface without assigning an explicit IP address to the inter-

face, use the ip numbered type number interface configuration command. In the commandtype

number indicates the type and number of another interface on which the router has an assignedIP address.

Server Location

The server location is located in several ways:

A single server on a single remote medium Multiple servers on a single remote medium, sometimes called a server farm Multiple servers on multiple remote media

OSPF

Configuring OSPF in a Single Area

OSPF is a link-state technology, as opposed to a distance vector technology such as Routing In-formation Protocol (RIP). The OSPF protocol performs the two primary functions of every rout-

ing protocol algorithm: path selection and path switching.

The OSPF addresses the following issues:


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Speed of convergence Support for variable-length subnet masks (VLSMs) Network Reachability Use of bandwidth Method for path selection

Topologies found in OSPF are:

Broadcast multicast topologies Point-to-point topologies Nonbroadcast multiaccess (NBMA) topologies

OSPF Operation in a Broadcast Multiaccess Topology

Because OSPF topology is dependent on the status of a link between two routers, neighborrouters must recognize each other on the network before they can share information. This proc-

ess is done using theHello Protocol. The information contained in a Hello Packet is as follows:

Router ID Hello and dead intervals Neighbors Area-ID Router priority DR and BDR IP address Authentication password Stub area flag

The DR and BDR add value to the network in the following ways:

Reducing routing update traffic Managing link-state synchronization

OSPF Startup

The steps involved when routers running OSPF come up on a network.

1. Exchange Process2. Discovering Routes

OSPF over NBMA TopologyOSPF runs in two official modes in NBMA topologies:

Nonbroadcast Multiaccess (NBMA) Point-to-Multipoint


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NBMA Mode Neighborship

Consider the following before using this mode:

Full mesh and direct communication Stability of the network

Point-to-Multipoint Mode Neighborship

This mode has the following properties.

Does not require a fully meshed network Does not require static neighbor configuration Uses on IP subnet Duplicate LSA packets

Configuring OSPF over NBMA Topology

RFC compliant Modes NBMA Node Point-to-multipoint Mode

Cisco-defined Modes Point-to-multipoint nonbroadcast mode Broadcast mode Point-to-point mode

Interconnecting Multiple OSPF Areas

Multiple OSPF Areas

The following areas need to be addresses.

Frequent calculations of the shortest path first (SPF) algorithm Large routing table Large link-state table

The hierarchical topology of OSPF has the following advantages.

Reduced frequency of SPF calculations Smaller routing tables Reduced link-state update (LSU) overhead

Types of Routers


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1. Internal Router2. Backbone Router3. Area Border Router4. Autonomous System Boundary Router (ASBR)

Types of AreasThe characteristics that you assign an area control the type of route information that it receives.

The possible area types include the following.

Standard area Backbone area Stub area Totally stubby area Not-so-stubby area

Supporting Route Summarization

Summarization is the consolidation of multiple routes into a single advertisement. With summa-rization, only summarized routes will propagate into the backbone. Two types of summarization

exist, as follows:

1. Interarea route summarization2. External route summarization

EIGRP

Configuring EIGRP

EIGRP is a Cisco owned protocol that combines the advantages of link-state and distance vector

routing protocols. This hybrid protocol has the following features:

Rapid convergence Reduced bandwidth usage Multiple network layer support

EIGRP Operation

Elements of EIGRP operation are:

EIGRP Packets EIGRP neighbor relationship

EIGRP Packets

EIGRP uses the following five types of packets:

Hello Update


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Queries Replies ACK

EIGRP Reliability

EIGRPs reliability mechanism ensures delivery of critical route information to neighboringrouters. This information is required to allow EIGRP to maintain a loop-free topology. All pack-

ets carrying routing information are sent reliably.

Topology TableWhen the router dynamically discovers a new neighbor, it sends an update about the routes that it

knows to its new neighbor and receives the same from the new neighbor. These updates populate

what is known as the Topology Table.

Configuring EIGRP

Perform the following steps to configure EIGRP for IP.

1. Enable EIGRP and define the autonomous system.2. Indicate which networks are parts of the EIGRP autonomous system.3. If using serial links especially for the frame relay or SMD define the bandwidth of a link

for the purpose of sending routing update traffic on the link.

EIGRP Load BalancingLoad balancing is the capability of a router to distribute the traffic over all its network ports that

are the same distance from the destination address.

EIGRP and WAN Links

EIGRP is scalable on both point-to-point links and NBMA multipoint and point-to-point links. A

solid understanding of EIGRP operation coupled with knowledge of link speeds can yield an ef-ficient, reliable and scalable router configuration.

EIGRP Link Utilization

By default EIGRP will use up to 50 percent of the bandwidth declared on an interface or subin-terface. This percentage can be adjusted.

Using EIGRP in a Scalable NetworkThe following are some of the many variables that impact network scalability.

The amount of information exchanged between neighbors A topology change The depth of topology The number of alternative paths through the network


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BGP

Configuring Basic Border Gateway Protocol

BGP is an interdomain routing protocol also known as an EGP.

Two types of routing protocols are as follows:

Interior Gateway Protocol (IGP) Exterior Gateway Protocol (EGP)

BGP Use

BGP is used between autonomous systems. The main goal of BGP is to provide an interdomain

routing system that guarantees the loop-free exchange of routing information between twoautonomous systems. BGP routers exchange information about paths to destination network.

When to use BGP

Use when one of the following conditions exists.

The AS allows packets to transit through it to reach other autonomous systems. The AS has multiple connections to other autonomous systems. The flow of traffic entering and leaving the AS must be manipulated.

When not to use BGPDo not use BGP when one or more of the following conditions exist.

A single connection to the Internet or another AS. No concern for routing policy and route selection. Lack of memory or processor power on routers to handle constant BGP updates.

A limited understanding of route filtering and BGP path selection process. Low bandwidth between autonomous systems.

BGP Peers or Neighbors

Any two routers that have found a TCP connection to exchange BGP routing information arecalled peers or neighbors.

Policy-Based RoutingBGP allows policy decisions at the AS level to be enforced. This setting of policies or rules for

routing is known aspolicy-based routing.

Well Known AttributesA well-known attribute is one that all BGP implementations must recognize. These attributes are

propagated to BGP neighbors.


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Optional Attributes

An optional attribute need not be supported by all BGP implementations; it could be a private

attribute.

Defined BGP Attributes

The attribute defined by BGP includes the following.

Well-known, Mandatory Attributes: AS-path Next-hop Origin

Well-known, Discretionary Attributes: Local preference Atomic Aggregate

Optional, Transitive Attribute; Aggregator Community

Optional, Nontransitive Attribute; Multi-exit-discriminator (MED)

BGP SynchronizationThe BGP synchronization rule states that a BGP router should not use or advertise to an external

neighbor a route learned by IBGP, unless that route is local or is learned from the IGP.

BGP Message TypesBGP defines the following message types:

Open Keepalive Update Notification

An open message includes the following information:

Version My autonomous system Hold time BGP identifier (router ID) Optional parameters

An update message may include the following fields.


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Withdrawn routes Path attributes Network layer reachability information

Implementing BGP in Scalable Networks

Route ReflectorsRoute reflectors modify the BGP split horizon rule by allowing the router configured as the route

reflector to propagate routes learned by IBGP to other IBGP peers. The route reflector will have

a partial IBGP peering with other routers, which are calledclients.

Policy Control and Prefix Lists

The advantages of using prefix lists are as follows:

A significant performance improvement over access list in loading and route lookup oflarge lists.

Support for incremental modifications.Optimizing Routing Update Operation

What is redistribution?

Cisco routers allow internetworks using different routing protocols to exchange routing informa-

tion though a feature calledroute distribution.

Redistribution Considerations:

Routing feedback (loops) Incompatible routing information Inconsistent convergence time

Policy-based Routing

The benefits that can be achieved by implementing policy based routing in networks include thefollowing.

Source-based transit provider selection Quality of service Cost savings Load sharing


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Key Points to Remember

1. Remember when configuring serial 0 for OSPF in a point-to-point mode using subinter-faces, the first command will always be very similar to this:interface serial 0.1.-2-.

2. You will use the show ip ospf neighbor command to verify that OSPF interfaces areconfigured in the proper area and to display neighbor adjacencies?

3. OSPF is always better than RIPv.1 in a large network because OSPF has virtually nolimitations on reach and it supports variable length subnet masks.

4. When configuring OSPF Ethernet, you will always enter the commands in the followingorder:interface Ethernet 0

IP address

!

interface Ethernet 1

IP address

!

router ospf

network area

network area

5. Once the OSPF routing process is enabled the following command will select only therouters network interfaces to participate in an OSPF area:

Network area

6. Remember that OSPF can support variable length subnet mask (VLSM) because OSPFcarries subnet mask confirmation in the link advertisements.

7. You can use the trace route command to view routing tables and determine if a router isusing the best path to forward packets on a specific network?

8. Route summarization uses hierarchical routing to allow one route update to representmany downstream networks.

9. Know the following about BGP:


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Periodic keepalives are sent to verify TCP connectivity.

Reliability comes from using TCP port 179 as its transport.Topology awareness is kept current by routine periodic update.

BGP based routing allows policy decisions at the AS level to be enforced.

BGP allows an AS to send traffic to a neighboring AS intending that the traffictake a different route than from the traffic originating in the neighboring AS.

10. Know that VLSM allows a way of controlling the number of reliable hosts on the net-work by manipulating the mask in an attempt to efficiently allocate IP addresses.

11. Know that by default, the next hop attribute advertised by EBGP is carried into IBGP.12. Know that the default-information originate always command is required whenever

you want to propagate a default route into an OSPF autonomous system.

13.

Know that BGP communities allow routers to filter incoming or outgoing updates andthat they are indicators used by routers to allow other routers to make decisions based

upon these indicators.

14. Know that an autonomous system is a set of routers under a single technical administra-tion and that it uses IGPs to route packets to other autonomous systems and EGPs to

route packets within the autonomous system.

15. Know that routers running EBGP are usually directly connected and they need to be ableto reach each other.

16. Know that an EIGRP router determines when a neighbor is unavailable when the holdtime is exceeded.

17. Know that routers run EBGP in order to exchange BGP information with routers in otherautonomous systems.

18. There are three basic elements that are required for a router to be able to forward apacket:

1. The best route

2. Destination address

3. Summarized routes entry

19. Know that RIPv.1 routing updates do not support VLSM because they do not contain thesubnet mask.

20. Know that in a routing entry table that the time value represents an incrementing routerindicating how long the router has been in the table since the last update.


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21. Know that all learned router entries are kept in EIGRP routing table.22. Know that when configuring EIGRP for NBMA operation that is the purpose of IP

bandwidth-percentage EIGRP command is to adjust the % of bandwidths that EIGRP

packets can use on an individual router interface.

23. Know that a router running BGP with all the default settings will not use a route learnedby IBGP unless that route is learned from IGP, and it will not advertise a route learned by

IBGP to an external neighbor unless that route is learned from IGP.

24. Know that the redistributing dynamic routes into the BGP method of sending route in-formation into BGP routing protocol is not recommended?

25. Know that the neighbor IP addr/peer name weight command is usedto change the BGP wait attribute of updates coming from a neighbor router.

26. Know that when a full event mesh of BGP sessions is configured within an autonomoussystem that this may result in many BGP sessions being created, and that it may result in

using a significant amount of bandwidth on slow WAN links.

27. An autonomous system connected via BGP to more than one ISP is referred to as Multi-homed.

28. Know that the following three IP protocols support variable length subnet masks(VLSM):

1. RIPv.2

2. OSPF3. EIGRP

29. Know that in an OSPF area that once you configure an ABR as a stub and the area is atransit area for virtual links, it will no longer exchange information with other routers inthe area.

30. A metric is a routing table entry, which is used to indicate the best route to reach a desti-nation network?

31. The show controller command will allow you to determine whether a serial interface isconnected to a DTE or DCE cable.

32. Know that link state routing determines path by bandwidth-based values, and it sends up-dates rather than complete routing tables when a network change occurs.


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33. Know that a variable length subnet masks have a greater capability to use route summari-zation, and VLSMs allow for more hierarchical levels within an attesting plan.

34. In a multiarea OSPF network all areas that incorporate NBMA topology must be fullmesh, but cannot be configured as stub areas.

35. Know that variable length subnet masking supports hierarchical addressing and is spe-cifically used in the IP environment.

36. Know that in a multipoint WAN topology using EIGRP on a serial interface that youshould configure the bandwidth to be the product of a number of circuits multiplied by

CIRs provisioned for each circuit in the topology.

37. Know that the show ip eigrp route command displays only the current EIGRP entries inthe routing table.

38.

Know that when using routes with EIGRP route selection, the cost between the localrouter and the destination is a feasible distance.

39. Know that an EIGRP router discovers its neighbors when it receives acknowledgementsfor the transmitted hello packets.

40. Know that the no auto summary command is used to turn off automatic summarizationfor EIGRP routes.

41. Know that the route summarization feature in EIGRP enables it to reduce the size of therouting table.

42. Know that when a neighboring router has failed to respond to a query about the routewithin three minutes, the route is set to be stuck inactive.

43. Know that excess SLSA traffic and frequent routing table recalculations occur when alarge number of routers operate in a single OSPF area.

44. Know that with OSPF support of VLSM a multiple design ensures that addresses are al-located in an efficient manner, and summarization can be performed with different prefixlengths throughout the network.

45. Know that for purpose of participating in an OSPF DR/BDR election that the defaultrouter priority is 1.

46. Know that logical interfaces are more reliable than physical interfaces, and that when asubinterfaces state changes to down, the physical interface remains up when using sub-interfaces in an NBMA topology.


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47. Know that the show ip ospf virtual-link command is used to verify the status of anOSPF virtual link.

48. Know that the hierarchical nature of OSPF allows you to separate a single large area intosmaller areas.

49. Know that you should use BGP in the following three instances:1. When there are multiple connections to the Internet.

2. When the flow of traffic entering and leaving and autonomous systemmust be manipulated.

3. When an autonomous system allows packets to transit through it to reach

other autonomous systems.

50. Know that you should NOT use BGP in the following three instances:1. When there is a single connection to the Internet.2. When there is a low bandwidth connection between autonomous systems.

3. When a route selection to routes outside of your autonomous system is not

a concern.

51. Know that multiple OSPF areas are connected via an OSPF ABR.52. Know that when all of the frame relay interfaces belong to area 0 in a multiarea OSPF

network that summary LANs will be flooded throughout the area and all area 0 routers

will recalculate their routing tables in response to a topology changes in area 0.

53. Know that when an autonomous system is connected via BGP to more than one ISP thatlow memory and low CPU usage will result when the ISPs send only default routes to theautonomous system.

54. Know that OSPF router can only route when they are in full state.55. Know that by using a passive interface you can prevent all RIP routing updates from be-

ing sent through selected RIP interfaces without using access lists.

56. Know that with Cisco IOS release 11.2 or later, by default, FAST switching mode willallow the router to forward packets that match the established policy.

57. Know that when boundary routers receive route information form both IGRP and OSPFnetworks that they will select the IGRP information because of the better administrative

distance.

58. Know that the following routing protocols support multiple link network layer routedprotocols:


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1. OSPF

2. EIGRP3. RIPv.2

59.

Know that a router running BGP has one table that contains BGP information receivedfrom and sent to other routers and another table that contains IP routing information.

60. Know that BGP peers also known as neighbors.61. Know that you would use the clear ip bgp command to reset all BGP sessions on a

router.

62. Know that you can perform route summarization on an EIGRP network manually at anyinterface within the network.

63.

Know that you would use the permanentIP route command parameter if you are config-uring the static route on a router and you want to configure it so that if the interface asso-

ciated with route goes down it will still remain in the routing table.

64. Know the following three characteristics of distance vector routing:1. It is utilized by RIP and IGRP.2. It is a simplest routing protocol to configure.

3. It sends periodic updates even when no network change has occurred.

65. Know that when you have an autonomous system that is connected via BGP to more thanone ISP that the ISP will send only default routes into the autonomous system and the

path leading to the router with the lowest BGP router ID will be used by non BGP routersas the best path to any external address?

66. Know that you would use the router eigrp command ifyou want to enable EIGRP and define the autonomous system.

67. Know that a router on the Ethernet will update it routing table and forwards the updatedtable to all other routers in the internet work when it learns of a link state change

68. Know the router ospf command is mandatory to configure OSPF.

69. Know that no ip forward-protocol udp 49 command is configured on a router to preventTACACS UDP port 49 requests from being forwarded by the router.

70. Know that when you are configuring redistribution between dissimilar routing protocolswhen there is more than one traffic path connecting the domains that this approach can


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confuse the router in the network and should be avoided. Also, changing the default ad-

ministrative distance and establishing large default matrix can establish a large path

through the internetwork.

71. When configuring redistribution to advertise RIP routes into EIGRP on a boundary routeryou need to specify a speed metric with the default-metric command. This format of theMetric being specified should be bandwidth delay reliability load.

72. Know that during route filtering, routes to be filtered are selected using the standard ac-cess list.

73. Know that you would use the show ip route command to verify that redistribution is op-erating correctly on a network where you have configured redistribution between RIP andOSPF.

74. Know that when route distribution is required for two routing domains with dissimilarmetric structures to have complete topology awareness, that in good network design therouting domains only interconnect at the routers where the distribution is configured, and

that routes from one domain are assigned a speed metric to indicate their reachability

prior to being injected into the other domain.

75. Know that a Classful routing protocol does not carry the subnet mask within routing up-dates. However, Classless routing protocols use the subnet mask for each network in theirrouting updates.

76. Know that route maps can be defined either by name or by number, and once a matchcondition occurs, and the corresponding set of condition has been applied, execution of

the route map is terminated.

77. Know that when a router can learn the network topology using both RIP and IGRP, thatthe IGRP routes will be placed in the routing table because they have smaller administra-

tive distance.


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Building Scalable Cisco Networks (BSCN)

Practice Questions

1. You are configuring redistribution to advertise EIGRP routes into OSPF on aboundary router. Given the following configuration, what is the function of the 20

parameter in the redistribute command?

Router OSPF 76

Redistribute EIGRP 300 metric 20 subnets.

A: It places a metric limit of 20 subnets to be included in each OSPF route advertise-

ment.

2. Given the following router R3 configuration command, which three statements aretrue?

Router OSPF 110Network 192.168.32.0 0.0.0.255 area 2

Network 192.168.33.0 0.0.0.255 area 0

Area 2 stub no-summary

Area 2 default-cost 10

A: Area 2 is a totally stubby area.

R3 adds 10 to the internal cost when it gets the default route in to the stub area.Router 2 non-ABR routes will contain only intra-area routing information and a de-

fault route.

3. Router R1 uses a subnet mask 255.255.255.0 and sits on the boundary of area 0 andarea 1. Given the following router configuration, which three statements are true?

router OSPF 76

network 172.12.32.0 0.0.15.255 area 1

network 172.12.96.0 0.0.15.255 area 0

Area 0 range 172.12.96.0 255.255.224.0

Area 1 range 172.12.32.0 255.255.224.0

A: An interface on this router with IP address 172.12.32.124 is in area 1. All networks within the range of 172.12.32.0 to 172.12.63.0 will be summarized

from area 1 into area 0.Area 0 can act as a stub or transit area for routes including networks in the range172.12.96.0 to 255.255.224.0.

4. Given the following router configuration, which three statements are true?


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Router OSPF 76

Network 172.22.23.34 0.0.0.0 area 1

Network 172.18.0.0 0.0.255.255 area 0

A: This is an area border router.

This area connects area 1 to backbone.Any router interface with an address of 172.18.x.x is in area 0.

5. Given the route summarization entry 192.168.16.0/20, how many class C addressescan be summarized?

A: 8

6. Given the following configuration, which two statements are true?interface Ethernet 0.

ip address 172.16.80.77 255.255.255.0ip helper-address 172.16.90.255

A: BOOTP request on the interface Ethernet 0 will be forwarded to network172.16.90.0.

NetBIOS broadcasts from 172.16.80.0 will be sent as directed broadcasts to net-

work 172.16.90.0.

7. Given the following configuration commands, which two statements are true?router EIGRP 110.

network 172.16.0.0.

network 3.0.0.0.

A: Line 1 defines EIGRP as an IP routing process.

Line 2 causes all interfaces connected to network 172.16.0.0 to send EIGRP up-

dates to other EIGRP routers.

8. When configuring serial 1 for OSPF in NBMA mode, what is the correct combina-tion of commands?

A: Interface serial 0

IP OSPF network non broadcastRouter OSPF process ID

9. You have configured policy based routing on serial interface 0. Given the followingconfiguration, which statement about a package arriving on serial 0 is most correct?


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Interface serial 0

IP policy route-map demo

Route-map demo permit 10

Mach IP address 4

Set interface serial 2 serial 3

Access list 4 permit 10.3.3.2 0.0.0.0

A: If the packet was sourced from 10.3.3.2 it will be routed out interface serial 2 and

interface serial 3 in a load sharing fashion.

10. Which command must be redistributed for Ethernet 1 if you want the route 10.1.1.0advertised?

A: ip route 10.1.1.0 255.255.255.0 interface e1

11. Given the following router A configuration, what are two effects of the configura-tion on router A?

Router BGP 65000

Network 10.0.0.0

Neighbor 172.17.1.1 remote-AS 65000

A: Line three identifies a peer router to router A.The 65000 in line one identifies the AS that router A is in.

12. Which two addresses can be summarized by the address 172.30.16.0/20? A: 172.30.17.0/24

172.30.31.0/24

13. The 172.20.0.0 had an 8-bit subnet mask extension applied to create all of its sub-nets. One unused subnet is being used to create several additional subnets in sup-

port of a WAN deployment effort. Which subnet mask should be used to support

two host addresses on WAN segment?

A: 255.255.255.252

14. You want to configure router A as a BGP route detector and router B as its client.Which three commands are necessary on router A?


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AS 65000

AS 65500

B

A

C

A: Router BGP 65000

Route/reflector client 172.16.12.1Neighbor 172.16.12.1 remote-AS 65000.

15. Given the following partial information from the output of a BGP command onrouter A, what next HOP address will router A use when it sends data to network

172.20.0.0?

Network Next HOP Metric Locprf Weight Patch

172.20.0.0 10.10.10.2 100 65250 65000 I

10.10.20.2 0 120 65200 65000 I10.10.30.2 0 130 65000 I

10.10.40.2 0 140 65000 I

10.10.50.2 0 150 65300 65000 I

A: 10.10.50.2


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Index

advertisements....................................... 1, 11

Area Border Router ..................................... 6

ASBR ..........................................................6autonomous system .....7, 8, 9, 12, 13, 15, 16Autonomous System Boundary Router....... 6

Backbone area .............................................6

Backbone Router ......................................... 6bandwidth............1, 4, 6, 7, 8, 13, 14, 15, 17

BDR....................................................... 4, 14

BGP.............8, 9, 10, 11, 12, 13, 15, 16, 3, 4Border Gateway Protocol ............................ 8

Broadcast ................................................. 4, 5

CIDR ....................................................... 2, 3

Classful routing .....................................1, 17Classless Interdomain Routing.................... 2

Classless routing.................................... 1, 17

convergence............................... 1, 2, 4, 6, 10Discretionary Attributes .............................. 9

distance vector............................... 1, 3, 6, 16

DR .........................................................4, 14EGP ............................................................. 8

EIGRP ...........1, 6, 7, 12, 13, 14, 16, 17, 1, 2

Exterior Gateway Protocol .......................... 8

frame relay............................................. 7, 15

global addresses........................................... 3Hello Packet ................................................ 4

hierarchical addressing.......................... 2, 14IBGP.......................................... 9, 10, 12, 13

IGP ....................................................8, 9, 13

IGRP.......................................... 1, 15, 16, 17interface.........3, 7, 11, 13, 14, 15, 16, 1, 2, 3

Interior Gateway Protocol ........................... 8

Internal Router............................................. 6

Internet ..............................................2, 8, 15IP address ..............................2, 3, 4, 11, 1, 3

ip numbered ............................................... 3link-state.......................................... 3, 4, 5, 6Load balancing ............................................7

Load sharing.............................................. 10

LSA .........................................................2, 5Mandatory Attributes .................................. 9

maximum transmission unit ........................1

meshed network........................................... 5

metric....................................... 1, 13, 17, 1, 4multicast ..............................................1, 2, 4multipoint ......................................4, 5, 7, 14

NAT......................................................... 2, 3

NBMA................................. 4, 5, 7, 13, 14, 2network address..................................... 2, 16

Network Address Translation.................. 2, 3

nonbroadcast................................................ 5 Nonbroadcast multiaccess ........................... 4

Nontransitive Attribute................................ 9

Not-so-stubby area ......................................6

OSPF 2, 3, 4, 5, 11, 12, 13, 14, 15, 16, 17, 1,2

OSPF Areas ................................................. 5

point-to-point................................. 4, 5, 7, 11policy based routing ..............................10, 2

policy-based routing.................................... 8

prefix lists.................................................. 10protocol.......................... 1, 3, 6, 8, 13, 16, 17

redistribution .........................3, 10, 16, 17, 1

RFC .............................................................5

RIP......................................... 1, 3, 15, 16, 17

RIPv1........................................................... 1route distribution................................. 10, 17

route filtering......................................... 8, 17Route reflectors ......................................... 10

route summarization...... 2, 3, 6, 11, 14, 16, 2

Route Summarization.............................. 2, 6Routing Information Protocol ..................... 3

routing policy ..............................................8

Routing table ...............................................2

Server farm.................................................. 3shortest path first ......................................... 5

SPF .............................................................. 5split horizon............................................... 10Standard area ............................................... 6

Stub.............................................................. 4

Stub area...................................................... 6subinterface ................................................. 7


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subnet masks ..................... 1, 2, 4, 11, 13, 14

synchronization .......................................4, 9

TCP/IP......................................................... 1topologies ....................................................4

topology......................... 1, 4, 5, 7, 14, 15, 17

Topology Table ...........................................7Totally stubby area ...................................... 6

Transitive Attribute ..................................... 9

Unnumbered ................................................ 3

Variable Length Subnet Masks ...................2VLSMs..............................................2, 4, 14

WAN ...........................................7, 13, 14, 3

well-known attribute ................................... 8

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