Pass4sure 300-101 Dumps

1
Switch and Routing Protocols
CCNP Routing and Switching ROUTE 300-101
2
Overview

• Explain the significance of static routing
• Configure static and default routes
• Verify and troubleshoot static and default routes
  
• Identify the classes of routing protocols
• Identify distance vector routing protocols
• Identify link-state routing protocols
• Describe the basic characteristics of common
  routing protocols
• Identify interior gateway protocols
• Identify exterior gateway protocols
• Enable Routing Information Protocol (RIP) on a
  router

3
The Routing Table

• Before we begin lets see lets discuss the routing
  table and directly connected routes.
• This is information which is not in the
  curriculum, but will give you a better
  understanding of what is taking place.

4
Directly Connected Networks and the IP Routing
Table
RTAshow 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, - candidate default
U - per-user static route, o - ODR Gateway of
last resort is not set RTA

• The Routing Table prior to any interface
  configuration
• The command to view the IP Routing table is
  (priviledge or user mode)
• Router show ip route
• Currently, no routes in the routing table.

5
Directly Connected Networks and the IP Routing
Table
RTA(config)inter e 0 RTA(config-if)ip add
192.168.2.1 255.255.255.0 RTA(config-if)no
shutdown RTAshow ip route Codes C -
connected,.. ltOther codes and gateway information
omittedgt C 192.168.2.0/24 is directly
connected, Ethernet0 RTA

• Adding an ip address/mask to an interface tells
  the router that it is a member, Directly
  Connected to that network just like when a
  host computer is configured with an ip
  address/mask.
• Notice the route is shown with the subnet mask
  and the exit-interface.
• Dont forget the no shutdown
• Dont forget the interface must be in up and
  up

6
Directly Connected Networks and the IP Routing
Table
RTA debug ip routing RTA(config)inter e
0 RTA(config-if)ip add 192.168.2.1
255.255.255.0 RTA(config-if)no
shutdown 002856 RT add 192.168.2.0/24 via
0.0.0.0, connected metric 0/0 002856 RT
interface Ethernet0 added to routing
table RTAshow ip route Codes C - connected,..
ltOther codes and gateway information omittedgt C
192.168.2.0/24 is directly connected,
Ethernet0 RTA undebug all

• Viewing the Routing Table Process
• Use the debug ip routing command to view the
  Cisco IOS routing table process of adding a
  directly connected network to the routing table.
• When finished, be sure to use undebug all
• Debug commands are used to view detailed
  information about Cisco IOS processes more
  later.

7
Directly Connected Networks and the IP Routing
Table
RTA debug ip routing RTA(config)inter e
0 RTA(config-if)shutdown 003438 RT interface
Ethernet0 removed from routing table 003438
RT del 192.168.2.0 via 0.0.0.0, connected metric
0/0 003438 RT delete network route to
192.168.2.0 RTAshow ip route Codes C -
connected,.. ltOther codes and gateway information
omittedgt RTA undebug all

• Viewing the Routing Table Process
• Directly connected routes will also be removed if
  the link goes down.
• Directly connected routes will only be in the
  routing table if, it is not administratively
  down, the line is up and protocol is up
• For serial interfaces, dont forget the clock
  rate command on the router with the DCE cable
  neither interface will be up and up until
  both ends are configured correctly.

8
Directly Connected Networks and the IP Routing
Table
RTAshow ip route Codes C - connected,.. ltOther
codes and gateway information omittedgt C
172.16.0.0/16 is directly connected, Serial0 C
192.168.2.0/24 is directly connected,
Ethernet0 RTBshow ip route Codes C -
connected,.. ltOther codes and gateway information
omittedgt C 172.16.0.0/16 is directly
connected, Serial0 C 192.168.1.0/24 is
directly connected, Serial1 RTCshow ip
route Codes C - connected,.. ltOther codes and
gateway information omittedgt C 10.0.0.0/8 is
directly connected, Ethernet0 C 192.168.1.0/24
is directly connected, Serial1

• The Routing Tables
• Notice that the routers only know about their own
  directly connected networks.
• They are not sharing routing information because
  we have not configured any static routes or
  dynamic routing protocols.

9
Directly Connected Networks and the IP Routing
Table
RTC(config)inter e 0 RTC(config-if)ip add
10.1.0.1 255.255.0.0 RTCshow ip route Codes C
- connected,.. ltOther codes and gateway
information omittedgt 10.0.0.0/16 is subnetted, 1
subnets C 10.1.0.0 is directly connected,
Ethernet0 C 192.168.1.0/24 is directly
connected, Serial1 RTC

• Configuring an interface which has a subnet mask
  greater than the classful mask
• We will discuss this in much more detail later
  using the presentation The Routing Table.
• For now, notice that when the subnet mask is not
  a classful mask, but a subnetted /16 mask.
• The routing table information shows the route to
  the subnetted network
• The mask is shown in the above, parent classful
  network.

10
Directly Connected Networks and the IP Routing
Table
RTAshow ip route C 172.16.0.0/16 is directly
connected, Serial0 C 192.168.2.0/24 is
directly connected, Ethernet0 RTAping
172.16.0.1 !!!!! RTAping 172.16.0.2 !!!!! RTAp
ing 192.168.1.1 ..... RTAping
192.168.1.2 ..... RTAping 10.1.0.1 .....

• Routing Only directly connected hosts (routers)
• Routers can only reach networks known about in
  its own routing table.

11
Directly Connected Networks and the IP Routing
Table
RTAshow ip route C 172.16.0.0/16 is directly
connected, Serial0 C 192.168.2.0/24 is
directly connected, Ethernet0 RTAping
172.16.0.1 Sending 5, 100-byte ICMP Echos to
172.16.0.1, timeout is 2 seconds !!!!! Success
rate is 100 percent (5/5), round-trip min/avg/max
56/57/60 ms RTAping 172.16.0.2 !!!!!

• Routing Routing tables must have the necessary
  network routes
• Question If RTA can ping RTBs 172.16.0.2
  interface why cant it ping RTBs 192.168.1.1
  interface? - RTA does not have a route to it in
  its routing table.
• Question Would an extended ping from RTA, using
  the source IP address of 192.168.2.1 be able to
  ping 172.16.0.1 on RTB? Why or why not? Where
  does the echo request or echo reply fail?

12
Directly Connected Networks and the IP Routing
Table
RTAshow ip route C 172.16.0.0/16 is directly
connected, Serial0 C 192.168.2.0/24 is
directly connected, Ethernet0 RTBshow ip
route Codes C - connected,.. ltOther codes and
gateway information omittedgt C 172.16.0.0/16
is directly connected, Serial0 C
192.168.1.0/24 is directly connected,
Serial1 RTAping Protocol ip Target IP
address 172.16.0.2 Extended commands n
y Source address or interface 192.168.2.1 Sending
5, 100-byte ICMP Echos to 172.16.0.2, timeout is
2 seconds .....

• Routing Routing tables must have the necessary
  network routes
• Question Would an extended ping from RTA, using
  the source IP address of 192.168.2.1 be able to
  ping 172.16.0.1 on RTB? Why or why not?
• The echo request from RTA reaches RTB because RTA
  has a route to 172.16.0.0/16 in its routing
  table.
• However, the echo reply from RTB back to RTA
  fails, because RTB does not have a route for
  192.168.2.0/24 in its routing table.

13
Directly Connected Networks and the IP Routing
Table
RTAshow ip route Codes C - connected,.. ltOther
codes and gateway information omittedgt C
172.16.0.0/16 is directly connected, Serial0 C
192.168.2.0/24 is directly connected,
Ethernet0 RTBshow ip route Codes C -
connected,.. ltOther codes and gateway information
omittedgt C 172.16.0.0/16 is directly
connected, Serial0 C 192.168.1.0/24 is
directly connected, Serial1 RTCshow ip
route Codes C - connected,.. ltOther codes and
gateway information omittedgt 10.0.0.0/16 is
subnetted, 1 subnets C 10.1.0.0 is directly
connected, Ethernet0 C 192.168.1.0/24 is
directly connected, Serial1

• Routing Table Principles Revisited (Zinin, Cisco
  IP Routing)
• Every router makes its decision alone, based on
  the information it has in its own routing table.
• The fact that one router has certain information
  in its routing table does not mean that other
  routers have the same information.
• Routing information about a path from one network
  to another does not provide routing information
  about the reverse, or return path.

14
Routing Types
15
Static Route Operation
Hobokenshow ip route Codes C - connected, S -
static, S 172.16.1.0/24 1/0 is directly
connected, Serial0 C 192.168.2.0/24 is
directly connected, Ethernet0
16
ip route command

• RTR(config) ip route prefix mask address
  interface distance tag tag permanent
• prefix IP route prefix for the destination.
• mask Prefix mask for the destination.
• address IP address of the next hop that can be
  used to reach that network.
• interface Network interface to use
  (exit-interface)
• distance (Optional) An administrative distance.
• tag tag (Optional) Tag value that can be used as
  a "match" value for controlling redistribution
  via route maps. (CCNP Advanced Routing)
• Permanent (Optional) Specifies that the route
  will not be removed, even if the interface shuts
  down. (CCNP Advanced Routing)

17
Static Route Operation

• If the exit interface (gateway) is down the
  static route will not be put in the routing table.

18
Static Route Operation

• If the router cannot reach the outgoing interface
  that is being used in the route, the route will
  not be installed in the routing table.
• This means if that interface is down, the route
  will not be placed in the routing table.

19
Administrative Distance and Metric
Hobokenshow ip route Codes C - connected, S -
static, S 172.16.1.0/24 1/0 is directly
connected, Serial0 C 192.168.2.0/24 is
directly connected, Ethernet0

• administrative distance / routing metric (or
  cost)
• The cost for all static routes is 0
• The default administrative distance for static
  routes is 1

20
Administrative Distance

• Administrative Distance is the trustworthiness
  of the routing information.
• Lower the administrative distance the more
  trustworthy the information.
• If the router hears about a route to the same
  network from more than one source it will use the
  administrative distance to decide which route to
  put in the routing table.

21
Examples from the curriculum
22
Examples from the curriculum

• Two choices.
• We will see the differences in a moment.

23
Examples from the curriculum

• The network 0.0.0.0 and mask 0.0.0.0 are known as
  a default route
• Can be written 0.0.0.0/0
• Known as a quad zero route
• More later

24
Static Routing

• Some extra information on static routing that is
  not in the curriculum

25
Static Routing

• Router(config)ip route destination-prefix
  destination-prefix-mask address interface
  distance tag tag permanent

26
Static Routing

• Configuring static routes
• Routers do not need to configure static routes
  for their own directly connected networks.
• We need to configure static routes for networks
  this router needs to reach.
• We will need to configure static routes for the
  other routers as well, as routing information
  about a path from one network to another does not
  provide routing information about the reverse, or
  return path.
• Convergence When all the routers in the network
  (AS) have accurate and consistent information, so
  that proper routing and packet forwarding can
  take place.
• Convergence will not happen until all the routers
  have complete and accurate routing information,
  meaning we must configure static routes on all
  the routers before packets will be correctly
  delivered.

27
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0
Network/subnet route
Intermediate-Address (usually next-hop)

• Basic static route example
• Be sure to use the proper subnet mask!

28
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0

• Basic static route example (continued)
• 1/0 Administrative Distance / Metric
• Administrative Distance This is the
  trustworthiness of the routing information.
  The default administrative distance of static
  routes is 1.
• The Administrative Distance of a directly
  connected route is 0.
• Lower the AD the more trustworthy.
• If the router learns about a route to a network
  from more than one source, it will install the
  route with the lower administrative distance in
  the routing table.

29
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0

• Basic static route example (continued)
• 1/0 Administrative Distance / Metric
• Metric This is the cost of getting to this
  route, I.e. how far away this network is.
• The lower the cost, the closer the network.
• Static routes always show a cost of 0 even if
  it was configured with the intermediate address
  is multiple-hops away.
• Much more later.

30
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0
2
1

• Recursive Lookup
• The router knows it can get to 192.168.1.0/24
  network by forwarding the packets to the router
  at the ip address of 172.16.0.2
• How does the router know how to get to the ip
  address 172.16.0.2?
• It does a recursive lookup first (1) by looking
  up the 192.168.1.0/24 network and finding it
  needs to forward the packet to 172.16.0.2 the
  router then (2) looks up the 172.16.0.0 network
  and sees it can forward it out the interface
  Serial 0.

31
Static Routing
RTAdebug ip routing IP routing debugging is
on RTAconf t Enter configuration commands, one
per line. End with CNTL/Z. RTA(config)ip route
192.168.1.0 255.255.255.0 172.16.0.2 055348
RT add 192.168.1.0/24 via 172.16.0.2, static
metric 1/0 RTA(config)ip route 10.1.0.0
255.255.0.0 172.16.0.2 055438 RT add
10.1.0.0/16 via 172.16.0.2, static metric
1/0 RTA(config)undebug all

• Static Routes and the Routing Table Process
• Notice that the static route is entered into the
  routing table by the routing table process (debug
  ip routing) with a metric of 0.

32
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTA(config)ip route 10.1.0.0
255.255.0.0 172.16.0.2 RTB(config)ip route
192.168.2.0 255.255.255.0 172.16.0.1 RTB(config)i
p route 10.1.0.0 255.255.0.0 192.168.1.2 RTC(conf
ig)ip route 192.168.2.0 255.255.255.0
192.168.1.1 RTC(config)ip route 172.16.0.0
255.255.0.0 192.168.1.1

• Configuring all of the static routes
• Notice that the intermediate-address is always
  the next-hop ip address.
• This does not always have to be the case, and we
  will look at other options in the presentation on
  Static Routes- Additional Information
• Good idea to do a copy running-config
  startup-config if everything is working right.
• To verify the routes are in there, you can do a
• Router show running-config

33
Static Routing
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTA(config)ip route 10.1.0.0
255.255.0.0 172.16.0.2 RTAshow ip route Codes
C - connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 10.0.0.0/16 is
subnetted, 1 subnets S 10.1.0.0 1/0 via
172.16.0.2 S 192.168.1.0/24 1/0 via
172.16.0.2 C 192.168.2.0/24 is directly
connected, Ethernet0 RTAping 10.1.0.1 !!!!! RTAp
ing 192.168.1.2 !!!!! RTAping 192.168.1.1 !!!!!
34
Static Routing Recursive Lookups
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0
2
1

• Recursive Lookup
• The router knows it can get to 192.168.1.0/24
  network by forwarding the packets to the router
  at the ip address of 172.16.0.2
• How does the router know how to get to the ip
  address 172.16.0.2?
• It does a recursive lookup first (1) by looking
  up the 192.168.1.0/24 network and finding it
  needs to forward the packet to 172.16.0.2 the
  router then (2) looks up the 172.16.0.0 network
  and sees it can forward it out the interface
  Serial 0.

35
Static Routing Recursive Lookups
RTA(config)ip route 10.1.0.0 255.255.0.0
192.168.1.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 S 10.1.0.0/16 1/0 via
192.168.1.2 C 192.168.2.0/24 is directly
connected, Ethernet0
3
2
1

• Recursive Lookup (continued)
• We can take this even further.
• One route can be used to resolve the route of
  another.
• It doesnt matter how the routes are resolved,
  whether they are directly connected, static or
  dynamic.
• Note If an intermediate address cannot be
  resolved, that route and any routes it affects
  are not installed in the routing table.

36
Static Routing Recursive Lookups

• Note regarding recursive route lookups
• Every route that does not reference an
  exit-interface must finally be resolved via a
  route with an interface descriptor reference in
  the corresponding path descriptor a route with
  an exit-interface.
• Static routes cannot be recursively resolved and
  will not be in the routing table.
• Consider these three static routes
• Route1 ip route 10.1.0.0 255.255.0.0
  20.1.1.1
• Route2 ip route 20.1.0.0 255.255.0.0
  30.1.1.1
• Route3 ip route 30.1.0.0 255.255.0.0
  10.1.1.1
• Route1 is resolved by Route2 which is resolved by
  Route3.
• None of these routes are finally resolved via a
  route with an exit-interface.
• This leads to endless recursion.
• The routing table process will not permit these
  static routes to be entered in the routing table.
• Note Static default routes (coming soon) can
  never be resolved via another default route.
  (later)

37
Static Routing Routing Table Process
RTAdebug ip routing IP routing debugging is
on RTAconf t Enter configuration commands, one
per line. End with CNTL/Z. RTA(config)ip route
192.168.1.0 255.255.255.0 172.16.0.2 055348
RT add 192.168.1.0/24 via 172.16.0.2, static
metric 1/0 RTA(config)ip route 10.1.0.0
255.255.0.0 172.16.0.2 055438 RT add
10.1.0.0/16 via 172.16.0.2, static metric
1/0 RTA(config)undebug all

• Static Routes and the Routing Table Process
• Notice that the static route is entered into the
  routing table by the routing table process (debug
  ip routing) with a metric of 0.

38
Static Routing Point-to-Point Links
RTA(config)ip route 192.168.1.0 255.255.255.0
serial 0 RTAshow ip route Codes C - connected,
S - static, C 172.16.0.0/16 is directly
connected, Serial0 S 192.168.1.0/24 is
directly connected, Serial0 C 192.168.2.0/24
is directly connected, Ethernet0

• Need only to use only an exit interface.
• For point-to-point serial interfaces, the
  next-hop address in the routing table is never
  used by the packet-delivery procedure, so it is
  not needed. (It could even reference a bogus IP
  address.)
• Notice that the static route appears in the
  routing table as directly connected, however it
  is still a static route with an administrative
  distance of 1.

39
Static Routing Point-to-Point Links
RTA(config)ip route 192.168.1.0 255.255.255.0
172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Serial0 S 192.168.1.0/24
1/0 via 172.16.0.2 C 192.168.2.0/24 is
directly connected, Ethernet0
2
1

• Using an intermediate address instead of an
  exit-interface
• If an intermediate address is used on a static
  route via a point-to-point link, it is only used
  to find the exit-interface,
• This recursive lookup is unnecessary and takes
  extra processing.

40
Static Routing Ethernet interfaces
e1
e0
RTA(config)ip route 192.168.1.0 255.255.255.0
eth 1 172.16.0.2 RTAshow ip route Codes C -
connected, S - static, C 172.16.0.0/16 is
directly connected, Ethernet1 S 192.168.1.0/24
1/0 via 172.16.0.2 Ethernet1 C
192.168.2.0/24 is directly connected, Ethernet0

• Using both an intermediate address instead and an
  exit-interface
• Notice we changed 172.16.0.0 to an Ethernet link.
• Static routes via broadcast links, it is best to
  use both an exit interface and intermediate
  address.
• This saves the router from having to do a
  recursive route lookup for the intermediate
  address of 172.16.0.2, knowing the exit interface
  is Ethernet 0.

41
Static Route Rule of Thumb

• Static routes via point-to-point links
• It is best to configure static routes with only
  the exit interface.
• For point-to-point serial interfaces, the
  next-hop address in the routing table is never
  used by the packet-delivery procedure, so it is
  not needed. (It could even reference a bogus IP
  address.)
• Static routes via broadcast networks such as
  Ethernet
• It is best to configure static routes with both
  the next-hop address and the exit-interface.
• Using only an intermediate address
• What about static routes referencing only
  intermediate network address? In short, try to
  avoid using them. The reason is that these static
  routes are not bound to any interface, rely on
  intermediate address resolvability, and thus
  converge more slowly. They can also create
  unexpected routing loops. Alex Zinin, Cisco IP
  Routing
• NOTE Most of our examples in this course do not
  follow either of these rules-of-thumb but you
  may want to use it on your network.

42
Common uses for Static Routes

• Static routes in the real-world
• Soon we will learn about dynamic routing
  protocols (RIP, etc.), where routers can learn
  automatically about networks, without the manual
  configuration of static routes.
• Does this mean that static routes are never used
  in the real-world?
• No! Static routes are used in conjunction with
  dynamic routing protocols.
• It is common to use a static route where using a
  dynamic routing protocols would have
  disadvantages or where it just not needed.

43
Common uses for Static Routes
10.1.1.1/24
ISP
ip route 172.16.0.0 255.255.0.0 10.1.1.2
10.1.1.2/24
Cabrillo College
172.16.0.0/16

• Static routes in the real-world (continued)
• In the example above, there is only one route,
  link, between Cabrillo Colleges network and the
  ISP.
• When there is only a single route to a network,
  this is known as a stub network.
• It is very common for the ISP to have a static
  route pointing to its customers networks, in
  this case Cabrillo College.

44
Common uses for Static Routes
Default
10.1.1.1/24
ISP
ip route 172.16.0.0 255.255.0.0 10.1.1.2
10.1.1.2/24
Cabrillo College
172.16.0.0/16
ip route 0.0.0.0 0.0.0.0 10.1.1.1

• Static routes in the real-world (continued)
• What about Cabrillo College and sending packets
  to the ISP packets going to the Internet?
• It is also common for customer networks to use a
  special kind of static route, known as a default
  static route.
• Of course we will examine this later throughout
  the rest of this course, but for now we specify
  the network and mask as 0.0.0.0 0.0.0.0
  (pronounced quad-zero).
• This tells the router to forward all packets to
  this next-hop address (or exit interface) that do
  not have an explicit route in the routing table.

45
Common uses for Static Routes
Default
10.1.1.1/24
ISP
ip route 172.16.0.0 255.255.0.0 10.1.1.2
10.1.1.2/24
Cabrillo College
172.16.0.0/16
ip route 0.0.0.0 0.0.0.0 10.1.1.1
RTBshow ip route Gateway of last resort is
10.1.1.1 to network 0.0.0.0 C 172.16.0.0/16 is
directly connected, Ethernet0 10.0.0.0/24 is
subnetted, 1 subnets C 10.1.1.0 is directly
connected, Serial1 S 0.0.0.0/0 1/0 via
10.1.1.1

• Any packets not matching the routes 172.16.0.0/16
  or 10.1.1.0/24 are sent to the router 10.1.1.1
  where it is now their problem.

46
Summarizing static routes

• There are many times when a single static route
  can replace several static routes.
• In other words, summarizing several static routes
  into a single static route.

172.16.0.0/24
47
Summarizing static routes
172.16.0.0/24

• Baypointe
• Lets configure three static routes on Baypointe
  using either an intermediate-address or exit
  interface
•    Baypointe(config) ip route 172.16.1.0
  255.255.255.0 192.168.1.2
•    Baypointe(config) ip route 172.16.2.0
  255.255.255.0 192.168.1.2
•    Baypointe(config) ip route 172.16.3.0
  255.255.255.0 192.168.1.2

48
Summarizing static routes

• Baypointe
• The three static routes can be summarized into a
  single route
• Baypointe(config) ip route 172.16.1.0
  255.255.255.0 192.168.1.2
• Baypointe(config) ip route 172.16.2.0
  255.255.255.0 192.168.1.2
•    Baypointe(config) ip route 172.16.3.0
  255.255.255.0 192.168.1.2
• Summarized route
• Baypointe(config) ip route 172.16.0.0
  255.255.0.0 192.168.1.2
• The summarized route will now include all three
  subnets!
• Be sure to use the proper mask 255.255.0.0!
• Using a 255.255.255.0 mask will only route for
  172.16.0.0/24 subnet and not 172.16.1.0/24,
  172.16.2.0/24 or 172.16.3.0/24.

49
Summarizing static routes
172.16.0.0/24

• Baypointe
• Summarized route
•   Baypointe(config) ip route 172.16.0.0
  255.255.0.0 192.168.1.2
• Advantages
• Fewer routes in the routing table faster
  routing table lookup.
• Subnets can be added and deleted on 172.16.0.0
  network without having to change static route on
  Baypointe router.

50
Verify static routes
Copy running-config startup-config
51
Ping and Traceroute to troubleshoot
52
Routed Protocols vs. Routing Protocols
53
Autonomous Systems

• An autonomous system (AS) is a collection of
  networks under a common administration sharing a
  common routing strategy.
• To the outside world, an AS is viewed as a single
  entity. The AS may be run by one or more
  operators while presenting a consistent view of
  routing to the external world.
• The American Registry of Internet Numbers (ARIN),
  a service provider, or an administrator assigns
  an identifying number to each AS.

54
Autonomous Systems

• Misinformation! This is not the same as an AS
  number used by ISPs! Routing protocols, such as
  Ciscos IGRP, require assignment of a unique,
  autonomous system number.

55
Routing Protocols

• The goal of a routing protocol is to build and
  maintain the routing table.
• This table contains the learned networks and
  associated ports for those networks.
• Routers use routing protocols to manage
  information received from other routers,
  information learned from the configuration of its
  own interfaces, along with manually configured
  routes.

56
Types of Routing Protocols

• Distance Vector RIP, IGRP, EIGRP
• Link State OSPF, IS-IS
• Path Vector BGP
• Note IGRP and EIGRP are Cisco Proprietary

57
Distance Vector Routing Protocols
Router B receives information from Router A.
Router B adds a distance vector number (such as
a number of hops), which increases the distance
vector. Then Router B passes this new routing
table to its other neighbor, Router C. This same
step-by-step process occurs in all directions
between neighbor routers.

• Routing by rumor
• Each router receives a routing table from its
  directly connected neighbor routers.

58
Distance Vector Routing Protocols
59
Distance Vector Network Discovery
60
(No Transcript)
61
Distance Vector Network Discovery
62
Distance Vector Network Discovery
63
Distance Vector Network Discovery
Convergence!
64
Distance Vector Routing Protocols

• Routing table updates occur when the topology
  changes. As with the network discovery process,
  topology change updates proceed step-by-step from
  router to router.
• With some routing protocols routing tables
  updates happen on a periodic basis.

65
Routing Protocol Metrics (costs_

• RIP Hop Count
• IGRP and EIGRP Bandwidth, Delay, Reliability,
  Load
• Ciscos OSPF Bandwidth
• IS-IS Cost
• BGP Number of AS or policy

66
Link State Routing Protocol Operations

• Link-state advertisements (LSAs) A link-state
  advertisement (LSA) is a small packet of routing
  information that is sent between routers.
• Topological database A topological database is
  a collection of information gathered from LSAs.
• SPF algorithm The shortest path first (SPF)
  algorithm is a calculation performed on the
  database resulting in the SPF tree.
• Routing tables A list of the known paths and
  interfaces.

67
Link State Routing Protocol Operations

• We will discuss this in more detail later when it
  will make much more sense.

68
Link State Routing Protocol Operations
69
Link State Routing Protocol Operations
70
Path Determination

• A router determines the path of a packet from one
  data link to another, using two basic functions
• A path determination function
• A switching function

71
Path Determination

• The switching function is the internal process
  used by a router to accept a packet on one
  interface and forward it to a second interface on
  the same router.
• A key responsibility of the switching function of
  the router is to encapsulate packets in the
  appropriate frame type for the next data link.

72
Configuring Dynamic Routing
73
Configuring Dynamic Routing
GAD(config)router rip GAD(config-router)network
172.16.0.0
74
More later!
Router(config)router rip Router(config-router)ne
twork 172.16.0.0 Router(config-router)network
160.89.0.0

• The network command is used on only directly
  connected networks.
• With RIP and IGRP, only need to use the classful
  address (no subnets).

• Network command two things
• Tells the router which interfaces that will
  participate in this dynamic routing protocol,
  which interfaces it will send and receive routing
  updates on.
• Tells other routers the networks in its routing
  updates that it is directly connect to.

75
More later!
Router(config)router rip Router(config-router)ne
twork 172.16.0.0 Router(config-router)network
160.89.0.0
76
Routing Protocols

• RIP A distance vector interior routing protocol
  
• IGRP Cisco's distance vector interior routing
  protocol
• OSPF A link-state interior routing protocol
• EIGRP Ciscos advanced distance vector interior
  routing protocol
• BGP A distance vector exterior routing protocol

77
Routing Protocols

• Routing Information Protocol (RIP) was originally
  specified in RFC 1058.
• It is a distance vector routing protocol.
• Hop count is used as the metric for path
  selection.
• If the hop count is greater than 15, the packet
  is discarded.
• Routing updates are broadcast every 30 seconds,
  by default.
• Interior Gateway Routing Protocol (IGRP) is a
  proprietary protocol developed by Cisco.
• It is a distance vector routing protocol.
• Bandwidth, load, delay and reliability are used
  to create a composite metric.
• Routing updates are broadcast every 90 seconds,
  by default.
• EIGRP is a Cisco proprietary enhanced distance
  vector routing protocol.
• It is an enhanced distance vector routing
  protocol.
• Uses unequal-cost and equal-cost load balancing.
• Uses a combination of distance vector and
  link-state features.
• Uses Diffused Update Algorithm (DUAL) to
  calculate the shortest path.
• NO! Routing updates are broadcast every 90
  seconds or as triggered by topology changes.

78
Routing Protocols

• Open Shortest Path First (OSPF) is a
  nonproprietary link-state routing protocol.
• It is a link-state routing protocol.
• Open standard routing protocol described in RFC
  2328.
• Uses the SPF algorithm to calculate the lowest
  cost to a destination.
• Routing updates are flooded as topology changes
  occur.
• Intermediate System to Intermediate System
  (IS-IS)
• IS-IS is an Open System Interconnection (OSI)
  routing protocol originally specified by
  International Organization for Standardization
  (ISO) 10589.
• It is a link-state routing protocol.
• Border Gateway Protocol (BGP) is an exterior
  routing protocol.
• It is a distance vector (or path vector) exterior
  routing protocol
• Used between ISPs or ISPs and clients.
• Used to route Internet traffic between autonomous
  systems.

79
IGP vs EGP

• Much of this information is too early to discuss.
• Interior routing protocols are designed for use
  in a network whose parts are under the control of
  a single organization.
• An exterior routing protocol is designed for use
  between two different networks that are under the
  control of two different organizations.

80
Distance Vector Algorithm

• Distance vector algorithms (also known as
  Bellman-Ford algorithms) call for each router to
  send all or some portion of its routing table
  only to its neighbors.
• Distance vector algorithms perform routing
  decisions based upon information provided by
  neighboring routers.
• Distance vector protocols use fewer system
  resources but can suffer from slow convergence
  and may use metrics that do not scale well to
  larger systems.

81
Link State Algorithm

• Link-state algorithms (also known as shortest
  path first algorithms) flood routing information
  to all routers in the internetwork that creates a
  map of the entire network.
• Misinformation, this is not the reason why.
  Because they converge more quickly than distance
  vector protocols, link-state algorithms are less
  prone to routing loops.

82
Summary