Cisco - Deploying EIGRP, IGRP 307

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© 1999, Cisco Systems, Inc.

Deployment of IGRP/EIGRP Session 307

307 0978_05F9_c2

© 1999, Cisco Systems, Inc.

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Understanding EIGRP

Understanding and deploying EIGRP is like driving a car 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary © 1999, Cisco Systems, Inc.

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IGRP: Interior Gateway Routing Protocol • Cisco proprietary • Distance vector • Broadcast based • Utilizes link bandwidth and delay 15 hops is no longer the limit

• 90 seconds updates (RIP is 30 sec.) • Load balance over unequal cost paths 307 0978_05F9_c2

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IGRP Metrics Calculation

• Metric = [K1 x BW + (K2 x BW) / (256 - Load) + K3 x Delay] x [K5 / (Reliability + K4)] By Default: K1 = 1, K2 = 0, K3 = 1, K4 = K5 = 0

• Delay is sum of all the delays of the link along the paths Delay = Delay/10

• Bandwidth is the lowest bandwidth of the link along the paths Bandwidth = 10000000/Bandwidth 307 0978_05F9_c2

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Problems with RIP and IGRP • Slow convergence • Not 100% loop free • Don’t support VLSM and discontiguous network • Periodic full routing updates • RIP has hop count limitation 307 0978_05F9_c2

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Advantages of EIGRP • Advanced distance vector • 100% loop free • Fast convergence • Easy configuration • Less network design constraints than OSPF • Incremental update • Supports VLSM and discontiguous network • Classless routing • Compatible with existing IGRP network • Protocol independent (support IPX and appletalk) 307 0978_05F9_c2

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Advantages of EIGRP • Uses multicast instead of broadcast • Utilize link bandwidth and delay EIGRP Metric = IGRP Metric x 256 (32 bit Vs. 24 bit)

• Unequal cost paths load balancing • More flexible than OSPF Full support of distribute list Manual summarization can be done in any interface at any router within network 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

EIGRP Packets • Hello: Establish neighbor relationships • Update: Send routing updates • Query: Ask neighbors about routing information • Reply: Response to query about routing information • Ack: Acknowledgement of a reliable packet 307 0978_05F9_c2

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EIGRP Neighbor Relationship • Two routers become neighbors when they see each other’s hello packet Hello address = 224.0.0.10

• Hellos sent once every five seconds on the following links: Broadcast Media: Ethernet, Token Ring, fddi, etc. Point-to-point serial links: PPP, HDLC, point-topoint frame relay/ATM subinterfaces Multipoint circuits with bandwidth greater than T1: ISDN PRI, SMDS, Frame Relay 307 0978_05F9_c2

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EIGRP Neighbor Relationship • Hellos sent once every 60 seconds on the following links: Multipoint circuits with bandwidth less than T1: ISDN BRI, Frame Relay, SMDS, etc.

• Neighbor declared dead when no EIGRP packets are received within hold interval Not only Hello can reset the hold timer

• Hold time by default is three times the hello time 307 0978_05F9_c2

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EIGRP Neighbor Relationship • EIGRP will form neighbors even though hello time and hold time don’t match • EIGRP sources hello packets from primary address of the interface • EIGRP will not form neighbor if K-values are mismatched • EIGRP will not form neighbor if AS numbers are mismatched • Passive interface (IGRP vs. EIGRP) 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

Discovering Routes B

A 1

afadjfjorqpoeru 39547439070713

Hello

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I am Router A, Who Is on the Link?

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Discovering Routes B

A afadjfjorqpoeru 39547439070713

1

Hello

I am Router A, Who Is on the Link? afadjfjorqpoeru 39547439070713

Here Is My Routing Information (Unicast)

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Update

2

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© 1999, Cisco Systems, Inc.

Discovering Routes B

A afadjfjorqpoeru 39547439070713

1

Hello

I am Router A, Who Is on the Link? afadjfjorqpoeru 39547439070713

Here Is My Routing Information (Unicast)

Update

2

afadjfjorqpoeru 39547439070713

3

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Ack

Thanks for the Information!

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Discovering Routes B

A afadjfjorqpoeru 39547439070713

1

Hello

I am Router A, Who Is on the Link? afadjfjorqpoeru 39547439070713

Here Is My Routing Information (Unicast)

Update

2

afadjfjorqpoeru 39547439070713

4

3

Ack

Topology Table

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Thanks for the Information!

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© 1999, Cisco Systems, Inc.

Discovering Routes B

A afadjfjorqpoeru 39547439070713

1

Hello

I am Router A, Who Is on the Link? afadjfjorqpoeru 39547439070713

Here Is My Routing Information (Unicast)

Update

2

afadjfjorqpoeru 39547439070713

4

3

Topology Table

5

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Ack

Thanks for the Information!

afadjfjorqpoeru 39547439070713

Update

Here Is My Route Information (Unicast)

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Discovering Routes B

A afadjfjorqpoeru 39547439070713

1

Hello

I am Router A, Who Is on the Link? afadjfjorqpoeru 39547439070713

Here Is My Routing Information (Unicast)

2

Update

afadjfjorqpoeru 39547439070713

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3

Topology Table

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Ack

Thanks for the Information!

afadjfjorqpoeru 39547439070713

Update

Here Is My Route Information (Unicast) afadjfjorqpoeru 39547439070713

Thanks for the Information!

Ack

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Converged 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary © 1999, Cisco Systems, Inc.

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EIGRP DUAL • Diffusing update algorithm • Finite-State-Machine Track all routes advertised by neighbors Select loop-free path using a successor and remember any feasible successors If successor lost Use feasible successor If no feasible successor Query neighbors and recompute new successor 307 0978_05F9_c2

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EIGRP Feasible Distance (FD)

• Feasible distance is the minimum distance (metric) along a path to a destination network

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Feasible Distance Example

A

(100)

H

(100)

B

(100)

D

Destination Destination

Topology Table

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Network 7 (10) G

(20) (1) FDDI

(100)

E

C (20)

F

(10)

Neighbor Neighbor

7

Feasible Distance (FD) 100+20+10=130

7

100+1+10+10=121

B

7

100+100+20+10+10=240

D

H

© 1999, Cisco Systems, Inc.

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EIGRP Reported Distance (RD)

• Reported distance is the distance (metric) towards a destination as advertised by an upstream neighbor Reported distance is the distance reported in the queries, the replies and the updates

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Reported Distance Example

(100)

H

(1)

(100) (100)

A

Destination Destination

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FDDI

B D

Topology Table

Network 7 (10) G

(20)

(100)

E

C (20)

F

(10)

Reported Reported Distance Distance (RD) (RD)

Neighbor Neighbor

7

20+10=30

H

7

1+10+10=21

B

7

100+20+10+10=140

D

© 1999, Cisco Systems, Inc.

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EIGRP Feasibility Condition (FC)

• A neighbor meets the feasibility condition (FC) if the reported distance by the neighbor is smaller than the feasible distance (FD) of this router

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EIGRP Successor

• A successor is a neighbor that has met the feasibility condition and has the least cost path towards the destination • It is the next hop for forwarding packets • Multiple successors are possible (load balancing) 307 0978_05F9_c2

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EIGRP Feasible Successor (FS)

• A feasible successor is a neighbor whose reported distance (RD) is less than the feasible distance (FD)

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Successor Example

(100)

H

(1)

(100) (100)

A

FDDI

B D

Destination Destination

Topology Table

Network 7 (10) G

(20)

(100)

E

C (20)

F

(10)

RD

Neighbor Neighbor

7

FD 130

30

H

7

121

21

B

7

240

140

D

Router A’s Routing Table 7 121 B

• B is current successor (FD = 121) • H is the feasible successor (30 < 121) 307 0978_05F9_c2

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Passive, Active, and Stuck in Active (SIA) • Passive routes are routes that have successor information Passive route = Good

• Active routes are routes that have lost their successors and no feasible successors are available. The router is actively looking for alternative paths Active route = Bad

• Stuck in Active means the neighbor still has not replied to the original query within three minutes Stuck in active = Ugly 307 0978_05F9_c2

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Dual Algorithm • Local computation When a route is no longer available via the current successor, the router checks its topology table Router can switch from successor to feasible successor without involving other routers in the computation Router stays passive Updates are sent 307 0978_05F9_c2

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DUAL: Local Computation (10)

H #2

#1

#8

B

(10)

#7 #7

. . .

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121/21 B 130/30 H

. . .

G

(20)

A

. . .

FDDI

D

E

(100)

#6

C

#3

X

(1) #4 (100)

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#7

#5

F

(10)

(20)

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Dual Algorithm • Diffused Computation When a route is no longer available via its current successor and no feasible successor is available, queries are sent out to neighbors asking about the lost route The route is said to be in active state Neighbors reply to the query if they have information about the lost route. If not, queries are sent out to all of their neighbors. The router sending out the query waits for all of the replies from its neighbors and will make routing decision based on the replies 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

DUAL: Diffused Computation (10)

H

#2 #1

A

. . .

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#8

121/21 B 130/30 H

. . .

. . .

G

(20)

B

(10)

#7 #7

X X

#7

#6

C

#3 FDDI

(1)

(100)

D #4

E

(100)

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#5

F

(10)

(20)

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DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D Cost (4/2) (fs) via E Cost (4/3)

(a)

A

(1)

D (a)

(1)

X

B

(2)

(2)

D

E

(1)

(a) (1)

C 307 0978_05F9_c2

E

EIGRP Topology Cost (2) (fd) via B Cost (2/1) (Successor) via C Cost (5/3) EIGRP Topology Cost (3) (fd) via D Cost (3/2) (Successor) via C Cost (4/3) 35

© 1999, Cisco Systems, Inc.

DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D via E Cost (4/3)

(a)

A

(1)

D

B

D

(2) C 307 0978_05F9_c2

(2) Q (1)

EIGRP Topology (a) ** **ACTIVE ACTIVE** ** Cost (-1) **ACTIVE** via E via C Cost (5/3)

E

(1) Q

(a) E

((fd) (fd fd)) (q) (q)

EIGRP Topology Cost (3) (fd) via D Cost (3/2) (Successor) via C Cost (4/3)

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DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D via E

(a)

A

(1)

D

B

D (2)

(2)

R

E

(1)

(1)

C

E

Q 307 0978_05F9_c2

EIGRP Topology (a) ** **ACTIVE ACTIVE** ** Cost (-1) (fd) **ACTIVE** via E (q) via C Cost (5/3) EIGRP Topology (a) ** **ACTIVE ACTIVE** ** Cost (-1) (fd) **ACTIVE** via D via C Cost (4/3) (q) 37

© 1999, Cisco Systems, Inc.

DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D via E

(a)

A

(1)

D

B

D

(2)

(2)

EIGRP Topology (a) ** **ACTIVE ACTIVE** ** Cost (-1) (fd) **ACTIVE** via E (q) via C Cost (5/3)

E

(1)

(a) C

(1)

E R

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EIGRP Topology Cost (4) (fd) via C Cost (4/3) (Successor) via D

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DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D via E

(a)

A

(1)

D (a)

B

D R (2)

(2)

E

(1)

(a) (1)

C 307 0978_05F9_c2

E

EIGRP Topology Cost (5) via C Cost (5/3) via E Cost (5/4)

(fd) (Successor) (Successor)

EIGRP Topology Cost (4) (fd) via C Cost (4/3) (Successor) via D 39

© 1999, Cisco Systems, Inc.

DUAL Example C EIGRP Topology (a) Cost (3) (fd) via B Cost (3/1) (Successor) via D via E

(a)

A

(1)

D (a)

B

D

(2)

(2)

E

(1)

(a) C 307 0978_05F9_c2

(1)

E

EIGRP Topology Cost (5) via C Cost (5/3) via E Cost (5/4)

(fd) (Successor) (Successor)

EIGRP Topology Cost (4) (fd) via C Cost (4/3) (Successor) via D

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DUAL Example (Start) C

(a)

(a) A

(1)

D (a)

(1)

B

(2)

(2)

D

E

(1)

(a) (1)

C 307 0978_05F9_c2

E

EIGRP Topology Cost (3) (fd) via B Cost (3/1) (Successor) via D Cost (4/2) (fs) via E Cost (4/3) EIGRP Topology Cost (2) (fd) via B Cost (2/1) (Successor) via C Cost (5/3) EIGRP Topology Cost (3) (fd) via D Cost (3/2) (Successor) via C Cost (4/3) 41

© 1999, Cisco Systems, Inc.

DUAL Example (End) C

(a)

(a) A

(1)

D (a)

B

D

(2)

(2)

E

(1)

(a) C 307 0978_05F9_c2

(1)

E

EIGRP Topology Cost (3) (fd) via B Cost (3/1) (Successor) via D via E EIGRP Topology Cost (5) via C Cost (5/3) via E Cost (5/4)

(fd) (Successor) (Successor)

EIGRP Topology Cost (4) (fd) via C Cost (4/3) (Successor) via D

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EIGRP Reliable Transport Protocol • EIGRP reliable packets are packets that requires explicit acknowledgement: Update Query Reply

• EIGRP unreliable packets are packets that do not require explicit acknowledgement: Hello Ack 307 0978_05F9_c2

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EIGRP Reliable Transport Protocol • The router keeps a neighbor list and a retransmission list for every neighbor • Each reliable packet (Update, Query, Reply) will be retransmitted when packet is not acked • EIGRP transport has window size of one (stop and wait mechanism) Every single reliable packet needs to be acknowledged before the next sequenced packet can be sent 307 0978_05F9_c2

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EIGRP Reliable Transport Protocol • With reliable multicast traffic, one must wait to transmit the next reliable multicast packets, until all peers have acknowledged the previous multicast • If one or more peers are slow in acknowledging, all other peers suffer from this • Solution: The nonacknowledged multicast packet will be retransmitted as a unicast to the slow neighbor 307 0978_05F9_c2

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EIGRP Reliable Transport Protocol

• Per neighbor, retransmission limit is 16 • Neighbor relationship is reset when retry limit (limit = 16) for reliable packets is reached

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Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary 47

© 1999, Cisco Systems, Inc.

EIGRP Summarization • Purpose: Smaller routing tables, smaller updates, query boundary • Auto summarization: On major network boundaries, networks are summarized to the major networks Auto summarization is turned on by default 150.150.X.X

151.151.X.X 150.150.X.X

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EIGRP Summarization • Manual summarization Configurable on per interface basis in any router within network When summarization is configured on an interface, the router immediate creates a route pointing to null zero with administrative distance of five Loop prevention mechanism When the last specific route of the summary goes away, the summary is deleted The minimum metric of the specific routes is used as the metric of the summary route 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

EIGRP Summarization • Manual summarization command: ip summary-address eigrp AS 1 50.2.0.0/16

50.3.0.0/16

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50.2.0.0/15 S0 interface s0 ip address 50.1.1.1 255.255.0.0 ip summary-address eigrp 1 50.2.0.0 255.254.0.0

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EIGRP Load Balancing • Routes with equal metric to the minimum metric, will be installed in the routing table (Equal Cost Load Balancing) • There can be up to six entries in the routing table for the same destination (default = 4) ip maximum-paths 307 0978_05F9_c2

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EIGRP Unequal Cost Load Balancing • EIGRP offers unequal cost load balancing feature with the command: Variance

• Variance command will allow the router to include routes with a metric smaller than multiplier times the minimum metric route for that destination, where multiplier is the number specified by the variance command 307 0978_05F9_c2

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Variance Example B E

20 10

Variance 2

20

10 C

D

10

A Net X

25

• Router E will choose router C to get to net X FD=20 • With variance of 2, router E will also choose router B to get to net X • Router D will not be used to get to net X 307 0978_05F9_c2

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© 1999, Cisco Systems, Inc.

Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary © 1999, Cisco Systems, Inc.

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EIGRP and IGRP Interaction • Administrative distance vs. routing metrics Administrative distance is used to compare with routes coming from two different routing protocols Connected = 0 Static route = 1 EIGRP summary route = 5 EBGP = 20 Internal EIGRP = 90 IGRP = 100 OSPF = 110 RIP = 120 External EIGRP = 170 IBGP = 200 307 0978_05F9_c2

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EIGRP and IGRP Interaction

• Metric is used to compare routes coming from the same routing protocol RIP = Hop count EIGRP/IGRP = Bandwidth and delay OSPF = Link cost 307 0978_05F9_c2

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EIGRP and IGRP Interaction • External vs. Internal EIGRP External EIGRP: Any routes being redistributed into an EIGRP process from another routing protocol or EIGRP process is considered as external EIGRP routes Administrative distance = 170 Internal EIGRP: Any routes that originated from its own EIGRP process is considered as internal EIGRP routes Administrative distance = 90 307 0978_05F9_c2

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EIGRP and IGRP Interaction

• To make EIGRP compatible with existing IGRP network with minimum interruption, EIGRP and IGRP with the same process number will be automatically redistributed into each other 307 0978_05F9_c2

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EIGRP and IGRP Interaction • Rules for IGRP/EIGRP interaction to avoid routing loops: Internal EIGRP routes preferred over IGRP routes Administrative distance considered (90 vs. 100) External EIGRP routes preferred over IGRP routes on same AS number and same scaled route metric Administrative distance not considered 307 0978_05F9_c2

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EIGRP/IGRP Example IGRP 2

EIGRP 1 B

C

FR

Ex ter nal Ne EIGR tX P

A External Net X

FR

D

RP IG E l na X ter Net x E

• Network X is external EIGRP route • Router A forwards external EIGRP routes to router B and D 307 0978_05F9_c2

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EIGRP/IGRP Example (Different AS) IGRP 2

C

et X PN IGR

EIGRP 1 B

FR

Ex ter nal Ne EIGR tX P

A External Net X

FR

IGR PN et X

D

RP EIG l na X ter Net Ex

• Router B and D sends IGRP route to router C • Router C sends IGRP network X route back to Router B and D • Router B and D will choose IGRP route because of lower Administrative distance Result: Router B and D will take the wrong route to Net X 307 0978_05F9_c2

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EIGRP/IGRP Example (Same AS) IGRP 1

C

et X PN IGR

EIGRP 1 B

FR

Ex ter nal Ne EIGR tX P

A External Net X

FR

IGR PN et X

D

RP IG E l na X ter Net x E

• Router B and D will not take administrative distance as decision process if EIGRP and IGRP has the same AS • Router B and D still favors external EIGRP routes from router A 307 0978_05F9_c2

Result: Router B and D will take correct route to Net X © 1999, Cisco Systems, Inc.

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Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary 63

© 1999, Cisco Systems, Inc.

EIGRP Query Process

• EIGRP is Advanced Distant Vector. It relies on its neighbor to provide routing information

Have You Seen My Sparky?

• If a route is lost and no feasible successor is available, EIGRP needs to converge fast, its only mechanism for fast convergence is to actively query for the lost route to its neighbors 307 0978_05F9_c2

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EIGRP Query Process • Queries are sent out when a route is lost and no feasible successor is available • The lost route is now in active state • Queries are sent out to all of its neighbors on all interfaces except the interface to the successor • If the neighbor does not have the lost route information, queries are sent out to their neighbors 307 0978_05F9_c2

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EIGRP Query Process • The router will have to get ALL of the replies from the neighbors before the router calculates the successor information • If any neighbor fails to reply the query in three minutes, this route is stuck in active and the router reset the neighbor that fails to reply • Solution is to limit query range to be covered later in presentation 307 0978_05F9_c2

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EIGRP Query Range • Autonomous System Boundaries Contrary to popular belief, queries are not bounded by AS boundaries. Queries from AS 1 will be propagated to AS 2

A

B

C

X

Network X AS 2

AS 1

Query for X

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Query for X

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EIGRP Query Range • Summarization point Auto or manual summarization is the best way to bound queries Requires a good address allocation scheme B Summarizes 130.0.0.0/8 to A A

B

129.x.x.x

C

X

130.130.1.0/24 130.x.x.x

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EIGRP Bandwidth Utilization • EIGRP by default will use up to 50% of the link bandwidth for EIGRP packets • This parameter is manually configurable by using the command: ip bandwidth-percent eigrp

• Use for greater EIGRP load control 307 0978_05F9_c2

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Bandwidth over WAN Interfaces

• Bandwidth utilization over point-topoint subinterface Frame Relay Treats bandwidth as T1 by default Best practice is to manually configure bandwidth as the CIR of the PVC

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Bandwidth over WAN Interfaces

• Bandwidth over multipoint Frame Relay, ATM, SMDS, and ISDN PRI: EIGRP uses the bandwidth on the main interface divided by the number of neighbors on that interface to get the bandwidth information per neighbor 307 0978_05F9_c2

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Bandwidth over WAN Interfaces • Each PVC might have different CIR, this might create EIGRP packet pacing problem Multipoint interfaces: Convert to point-to-point Bandwidth configured = (lowest CIR x number of PVC) ISDN PRI: Use Dialer Profile (treat as point-to-point link)

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Agenda • • • • • • • 307 0978_05F9_c2

Fundamentals of EIGRP DUAL Summarization and Load Balancing EIGRP/IGRP Interaction Query Process Deployment Guidelines with EIGRP Summary © 1999, Cisco Systems, Inc.

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Factors That Influence EIGRP Scalability

• Keep in mind that EIGRP is not plug and play for large networks • Limit EIGRP query range! • Quantity of routing information exchanged between peers 307 0978_05F9_c2

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Limiting Updates/Queries— Example Distribution Layer

Remote Sites

10.1.8.0/24

RTRC RTRB

RTRD

RTRA

RTRE 307 0978_05F9_c2

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Limiting Size/Scope of Updates/Queries

• Evaluate routing requirements What routes are needed where?

• Once needs are determined Use summary address Use distribute lists 307 0978_05F9_c2

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Limiting Updates/Queries— Example Distribution Layer

Remote Sites

X

10.1.8.0/24

Queries Replies

RTRC RTRB

RTRD

RTRA RTRE 307 0978_05F9_c2

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Limiting Updates/Queries—Summary

• Remote routers fully involved in convergence Most remotes are never intended to be transit Convergence complicated through lack of information hiding 307 0978_05F9_c2

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Limiting Updates/Queries—Better Distribution Layer Queries Replies

Remote Sites

X

10.1.8.0/24

RTRC RTRB

RTRD

RTRA IP summary-address eigrp 1 10.0.0.0 255.0.0.0 on all outbound interfaces to remotes 307 0978_05F9_c2

RTRE

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Limiting Updates/Queries— Summary

• Convergence simplified by adding the summary-address statements • Remote routers just reply when queried

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Hierarchy/Addressing

• Permits maximum information hiding • Advertise major net or default route to regions or remotes • Provides adequate redundancy

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EIGRP Scalability • EIGRP is a very scalable routing protocol if proper design methods are used: Good allocation of address space Each region should have an unique address space so route summarization is possible Have a tiered network design model (Core, Distribution, Access) 307 0978_05F9_c2

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EIGRP Scalability • Proper network resources Sufficient memory on the router Sufficient bandwidth on WAN interfaces

• Proper configuration of the “bandwidth” statement over WAN interfaces, especially over Frame Relay • Avoid blind mutual redistribution between two routing protocols or two EIGRP processes 307 0978_05F9_c2

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Tiered Network Design Summarized Routes

Summarized Routes

Other Regions

Other Regions Core

Other Regions Summarized Routes Distribution Layer

Summarized Routes Other Regions

Summarized Routes

Summarized Routes

Access Layer 307 0978_05F9_c2

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Nonscalable Network Core 1.1.1.0 1.1.2.0 2.2.3.0 3.3.4.0

2.2.1.0 3.3.2.0 3.3.3.0 1.1.4.0

3.3.1.0 2.2.2.0 1.1.3.0

2.2.1.0

1.1.1.0 3.3.4.0 Token Ring

Token Ring

2.2.3.0

1.1.2.0

Token Ring

Token Ring

3.3.1.0

1.1.4.0

Token Ring

3.3.4.0 3.3.3.0

1.1.3.0 Token Ring

2.2.2.0

• Bad addressing scheme Subnets are everywhere throughout entire network 307 0978_05F9_c2

• Queries not bounded 85

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Scalable Network Core 1.0.0.0

3.0.0.0 2.0.0.0 3.3.1.0

1.1.1.0 1.1.4.0 Token Ring

1.1.2.0

Token Ring

2.2.1.0

1.1.3.0

Token Ring

2.2.3.0 Token Ring

3.3.4.0 Token Ring

Token Ring

3.3.4.0 3.3.3.0

2.2.2.0

• Readdress network Each region has its own block of address

• Queries bounded by using “ip summary-address eigrp” command 307 0978_05F9_c2

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Summary • Query range Best way to limit query is through route summarization

• EIGRP is not plug and play for large networks It’s a very scalable protocol with little design requirement

• Optimizing EIGRP network Limiting query range Route summarization Tiered network design Sufficient network resources 307 0978_05F9_c2

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Please Complete Your Evaluation Form Session 307

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