CIS 185 Advanced Routing Protocols EIGRP Part 2 pot

CIS 185 Advanced Routing Protocols
EIGRP Part 2
Rick Graziani
Cabrillo College

Fall 2012
2
EIGRP Part 2

EIGRP over Frame Relay

EIGRP over MPLS

EIGRP Load Balancing

EIGRP Bandwidth across WAN Links

Authentication

EIGRP Scalability in Large Networks
3
Materials

Book:

Implementing Cisco IP Routing
(ROUTE) Foundation Learning
Guide: Foundation learning for the
ROUTE 642-902 Exam

By Diane Teare


Book

ISBN-10: 1-58705-882-0

ISBN-13: 978-1-58705-882-0

eBook

ISBN-10: 0-13-255033-4

ISBN-13: 978-0-13-255033-8
Configuring and Verifying
EIGRP in an Enterprise WAN
Physical Frame-Relay
Multipoint and point-to-point Frame-Relay subinterfaces
Multiprotocol Label Switching (MPLS) virtual private
networks (VPNs)
Ethernet over Multiprotocol Label Switching (EoMPLS)
4
Frame Relay Basics

Frame Relay Basics

A switched WAN technology

Virtual circuits (VCs) are created by a Service Provider (SP)

Multiple logical VCs to be multiplexed over a single physical interface.


Typically PVCs identified by a locally significant data link connection
identifier (DLCI).

For IP connectivity: A mapping between IP addresses and DLCIs must
be defined, either dynamically or statically.
5
Frame Relay Basics

By default, a Frame Relay network is an NBMA network.

Like multiaccess networks (Ethernet LANs) All routers are on the same
subnet

But broadcast (and multicast) packets CANNOT be sent just once as they
are in a broadcast environment such as Ethernet.

Cisco IOS implements pseudo-broadcasting

Router creates a copy of the broadcast or multicast packet for each
neighbor reachable through the WAN media (over the PVC).

Sends the copy of the broadcast or multicast packet over the appropriate
PVC for that neighbor.
6
EIGRP over Frame Relay:
Physical Interface with Dynamic Mapping

Inverse ARP is on by default

Automatically maps the IP address of the devices at the other end of the

PVCs to the local DLCI number.

Split horizon is disabled by default on Frame Relay physical interfaces.

Routes from Router R2 can be sent to Router R3, and vise-versa.

Note: Inverse ARP does not provide dynamic mapping for the
communication between routers R2 to R3 because they are not
connected with a PVC; this must be configured (mapped) manually
7
DLCI 100
DLCI 130
R1
Same Subnet
EIGRP over Frame Relay:
Physical Interface with Dynamic Mapping

R1 forms the adjacency with router R2 and R3 over the serial0/0
physical interface.

R3 (and R2) forms an adjacency with router R1.

No EIGRP relationship exists between routers R2 and R3.
8
EIGRP over Frame Relay:
Physical Interface with Static Mapping

Using static mapping disables Inverse ARP

No changes to the basic EIGRP configuration.


Manual IP-to-DLCI mapping commands on the serial 0/0 interface are
necessary on all three routers.

Again, because split horizon is disabled by default on Frame Relay
physical interfaces, routes from R2 can be sent to R3, and vise-versa.

Note: R1 includes a Frame Relay map to its own IP address so it can
ping its own interface.
9
R1
interface Serial 0/0
encapsulation frame-relay
ip address 192.168.1.103 255.255.255.0
frame-relay map ip 192.168.1.101 130 broadcast
router eigrp 110
network 192.168.1.0
R3
EIGRP over Frame Relay:
Physical Interface with Static Mapping

The adjacencies formed on R1 using static mapping are the same as those
formed using dynamic mapping.

R2 and R3 also form an adjacency with router R1.

R2 and R3 can also form an EIGRP adjacency to each other if the IP-to-
DLCI mapping for that connectivity is provided.

Output shows that R3 has two neighbors (router R1 and R2), indicating that

this mapping was provided on R3 (but not required between R2 and R3).
10
interface Serial 0/0
encapsulation frame-relay
ip address 192.168.1.103 255.255.255.0
frame-relay map ip 192.168.1.101 130 broadcast
frame-relay map ip 192.168.1.102 130 broadcast
router eigrp 110
network 192.168.1.0
R3
EIGRP over Frame
Relay:
Multipoint
Subinterfaces

Separating a physical interface into multipoint subinterfaces allows each
subinterface to be on a separate network.

Multipoint subinterfaces are configured with the command:
interface serial number.subinterface-number multipoint
11
DLCI 100
DLCI 130

DLCI 103
Same Subnet
EIGRP over Frame Relay:
Multipoint Subinterfaces

IP address-to-DLCI mapping on multipoint subinterfaces is done by either:


Specifying the local DLCI value (frame-relay interface-dlci dlci)
and relying on Inverse ARP

Using manual IP address-to-DLCI mapping.

The physical interface serial 0/0 is configured for Frame Relay
encapsulation and does not have an IP address assigned to it.

Note: The spoke router does not have a multipoint-subinterface.
12
R1
interface Serial 0/0
no ip address
encapsulation frame-relay
interface serial 0/0/0.1 multipoint
ip address 192.168.1.101 255.255.255.0
no ip split-horizon eigrp 110
frame-relay map ip 192.168.1.102 102 broadcast
frame-relay map ip 192.168.1.103 103 broadcast
router eigrp 110
network 192.168.1.0
network 172.16.1.0 0.0.0.255
R3
interface Serial 0/0
no ip address
encapsulation frame-relay
interface serial 0/0/0.1 multipoint
ip address 192.168.1.103 255.255.255.0
frame-relay map ip 192.168.1.101 130 broadcast

router eigrp 110
network 192.168.1.0
EIGRP over Frame Relay:
Multipoint Subinterfaces

Split horizon is enabled by default on Frame Relay multipoint interfaces.

R2 and R3 need to provide connectivity between their connected networks
so…

EIGRP split horizon is disabled on the multipoint subinterface of router R1
with the no ip split-horizon eigrp as-number command.
13
R1
interface Serial 0/0
no ip address
encapsulation frame-relay
interface serial 0/0/0.1 multipoint
ip address 192.168.1.101 255.255.255.0
no ip split-horizon eigrp 110
frame-relay map ip 192.168.1.102 102 broadcast
frame-relay map ip 192.168.1.103 103 broadcast
router eigrp 110
network 192.168.1.0
network 172.16.1.0 0.0.0.255
R3
interface Serial 0/0
no ip address
encapsulation frame-relay
interface serial 0/0/0.1 multipoint

ip address 192.168.1.103 255.255.255.0
frame-relay map ip 192.168.1.101 130 broadcast
router eigrp 110
network 192.168.1.0
EIGRP over Frame Relay:
Multipoint Subinterfaces

Verify with show ip eigrp neighbors

R1 forms an adjacency with routers R2 and R3 over the serial0/0.1
multipoint subinterface.

R2 and R3 form the adjacency with R1

Note: R2 and R3 could form an adjacency between each other if the IP
address-to-DLCI mapping for that connectivity is provided. (not required)
14
EIGRP over Frame Relay:
Unicast Neighbors

Not all Frame Relay service providers support multicasts/broadcasts so
routing information must be sent as unicasts.

router configuration command:
neighbor {ip-address | ipv6-address} interface-type interface-number

Defines a neighboring router to exchange EIGRP routing information.

Instead of using multicast packets, EIGRP exchanges routing information with
the specified neighbor using unicast packets.

15
R2R1
EIGRP over Frame Relay:
Unicast Neighbors

EIGRP does not process any multicast packets coming inbound on that
interface

EIGRP stops sending multicast packets on that interface.
16
R2R1
EIGRP over Frame Relay:
Unicast Neighbors

R1 is configured with a neighbor command for R2.

R1 will therefore not accept multicast packets on Serial 0/0.1 anymore.

R2 must also be configured with a neighbor command for R1 to establish
an adjacency.

R1 and R3 are not configured with a neighbor command for each other.

Therefore, R1 and R3 will not form an adjacency.
17
R2R1
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s
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t
i
c
a
s
t
EIGRP over Frame Relay:
Unicast Neighbors

Because R3 is not using the neighbor command it tries to communicate
with multicast packets on its Serial 0/0/.1.

However, neighborship is not established because neither R1 nor Router
R2 is accepting multicast packets.
18
R1
R3
interface Serial 0/0
no ip address
encapsulation frame-relay
interface serial 0/0/0.1 multipoint
ip address 192.168.1.103 255.255.255.0
frame-relay map ip 192.168.1.101 130 broadcast
router eigrp 110

network 192.168.1.0
EIGRP over Frame
Relay:
Point-to-Point
Subinterfaces

Point-to-point subinterfaces are logical interfaces:

Emulates a leased line network

Provide a routing equivalent to point-to-point physical interfaces

As with physical point-to-point interfaces, each interface requires its
own subnet.

Frame Relay point-to point is applicable to hub and spoke topologies.
19
DLCI 100
DLCI 130

DLCI 103
Same Subnet
EIGRP over Frame Relay:
Point-to-Point Subinterfaces

R1 and R3:

The physical interface serial 0/0 is configured for Frame Relay
encapsulation


The physical interface does not have an IP address assigned to it
20
EIGRP over Frame Relay:
Point-to-Point Subinterfaces

Point-to-point subinterfaces are created with the command:
interface serial number.subinterface-number point-to-point

IP address-to-DLCI mapping on point-to-point subinterfaces with:
frame-relay interface-dlci dlci

R1 has two point-to-point subinterfaces, one for each subnet and DLCI.

Note: R3 does not need a subinterface.
21
EIGRP over MPLS

MPLS (Multiprotocol Label Switching) is an IETF standard.

Combines the:

Advantages of Layer 3 routing

Benefits of Layer 2 switching

Short fixed-length labels are assigned to each packet at the edge of the
MPLS network.

Allows for scalable VPNs, end-to-end QoS, and other IP services that
allow efficient utilization of existing networks with simpler configuration,

management, and quicker fault correction.
22
What is MPLS?

New WAN technology originally defined in RFC 3031 by:

Cisco Systems

Force 10 Networks

Juniper networks

Started out as Tag Switching introduced by Ipsilon (now part of Nokia)
What is the problem MPLS is trying to solve?

Layer 3 End-to-end circuits

Advantages

IP routing provides dynamic, automatic path setup

Provides best path and backup paths

Provides QoS

Disadvantages

Latency in hop-by-hop Layer 3 lookup

Latency in routing – switching – packet forwarding process

What is the problem MPLS is trying to solve?

Layer 2 End-to-end circuits (ATM, Frame Relay)

Advantages

Circuits (SVC or PVC) means destinations are pre-established at
switches

Less latency, switched only - no Layer 3 lookups

Disadvantages

Circuits difficult to manage - must use management software or human
configuration.

QoS and SLAs are individually managed