EIGRP Default Route

1. EIGRP DEFAULT ROUTE
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2. • WITH THE USE OF DEFAULT ROUTES A BETTER NETWORK PERFORMANCE COULD BE
ACHIEVED.
• FOR EXAMPLE ROUTERS AT THE ACCESS LAYER DON’T NEED TO KNOW ALL ROUTES
IN WHOLE NETWORK.
• BY USING A DEFAULT ROUTE YOU CAN SIGNIFICANTLY REDUCE THE SIZE OF
ROUTER’S ROUTING TABLE THUS IMPROVING PERFORMANCE.
• THERE ARE FEW WAYS TO PROPAGATE A DEFAULT ROUTE INTO EIGRP DOMAIN,
• REDISTRIBUTED DEFAULT ROUTE
• DEFAULT ROUTE BY USING IP DEFAULT-NETWORK COMMAND
• DEFAULT ROUTE WITH NETWORK 0.0.0.0 COMMAND
• BY USING IP SUMMARY-ADDRESS COMMAND

4. ISP
• ISP(CONFIG)#INTERFACE FASTETHERNET 0/0
• ISP(CONFIG-IF)#IP ADDRESS 10.0.0.1 255.255.255.0
• ISP(CONFIG-IF)#NO SHUTDOWN
• ISP(CONFIG-IF)#INTERFACE LO 0
• ISP(CONFIG-IF)#IP ADDRESS 192.168.100.1 255.255.255.0
• ISP(CONFIG)#IP ROUTE 192.168.0.0 255.255.255.0 FASTETHERNET 0/0

5. BORDER
• BORDER(CONFIG)#INTERFACE FA0/0
• BORDER(CONFIG-IF)#IP ADDRESS 192.168.0.3 255.255.255.0
• BORDER(CONFIG-IF)#NO SHUTDOWN
• BORDER(CONFIG-IF)#INTERFACE FA0/1
• BORDER(CONFIG-IF)#IP ADDRESS 10.0.0.2 255.255.255.0
• BORDER(CONFIG-IF)#NO SHUTDOWN
• BORDER(CONFIG)#ROUTER EIGRP 1
• BORDER(CONFIG-ROUTER)#NETWORK 192.168.0.0 255.255.255.0

6. R1
• R1(CONFIG)#INTERFACE FA0/0
• R1(CONFIG-IF)#IP ADDRESS 192.168.0.1 255.255.255.0
• R1(CONFIG-IF)#NO SHUTDOWN
• R1(CONFIG)#ROUTER EIGRP 1
• R1(CONFIG-ROUTER)#NETWORK 192.168.0.0 255.255.255.0
R2
• R2(CONFIG)#INTERFACE FA0/0
• R2(CONFIG-IF)#IP ADDRESS 192.168.0.2 255.255.255.0
• R2(CONFIG-IF)#NO SHUTDOWN
• R2(CONFIG)#ROUTER EIGRP 1
• R2(CONFIG-ROUTER)#NETWORK 192.168.0.0 255.255.255.0

7. REDISTRIBUTED DEFAULT ROUTE
• TO REDISTRIBUTE A DEFAULT ROUTE INTO EIGRP, WE USED A STATIC DEFAULT ROUTE ON
BORDER WHICH POINTS TO ISP.
• BORDER(CONFIG)#IP ROUTE 0.0.0.0 0.0.0.0 10.0.0.1
• NOW, REDISTRIBUTION COMMAND
• BORDER(CONFIG-ROUTER)#REDISTRIBUTE STATIC METRIC 10000 100 255 1 1500

8. WHERE METRIC VALUES ARE:
• BANDWITH – 10000 KB/S (10 MB/S);
• DELAY – 100 (TENS OF MICROSECONDS, FOR 10MB/S INTERFACE WE HAVE 1000
MICROSECONDS);
• RELIABILITY – 255 (100% RELIABLE);
• LOADING – 1 (IF 255 THEN 100% LOADED);
• MTU – 1500.

9. SHOW IP ROUTE COMMAND AND SENT A PING TO ISP
LOOPBACK 0 INTERFACE
• R1#SHOW IP ROUTE
• ... OUTPUT OMITTED ...
• GATEWAY OF LAST RESORT IS 192.168.0.3 TO NETWORK 0.0.0.0
• C 192.168.0.0/24 IS DIRECTLY CONNECTED, FASTETHERNET0/0
• D*EX 0.0.0.0/0 [170/307200] VIA 192.168.0.3, 01:45:34, FASTETHERNET0/0
• R1#
• R1#PING 192.168.100.1
• TYPE ESCAPE SEQUENCE TO ABORT.
• SENDING 5, 100-BYTE ICMP ECHOS TO 192.168.100.1, TIMEOUT IS 2 SECONDS:
• !!!!!
• SUCCESS RATE IS 100 PERCENT (5/5), ROUND-TRIP MIN/AVG/MAX = 20/39/48 MS
• R1#

10. DEFAULT ROUTE BY USING IP DEFAULT-NETWORK COMMAND
• ANOTHER METHOD TO GENERATE A DEFAULT ROUTE IS BY USING IP DEFAULT-
NETWORK COMMAND.
• BUT FIRST TAKE INTO ACCOUNT FEW THINGS:
• DEFAULT NETWORK MUST BE REACHABLE BY THE ROUTER THAT ADVERTISE IT;
• ALL ROUTERS THAT RECEIVE DEFAULT NETWORK MUST KNOW HOW TO REACH IT THROUGH EIGRP.

11. • I CHOSE ISP’S LOOPBACK TO BE DEFAULT NETWORK AND ON BORDER I SET UP A
STATIC ROUTE AND THEN REDISTRIBUTED IT INTO EIGRP.
• BORDER(CONFIG)#IP ROUTE 192.168.100.0 255.255.255.0 FASTETHERNET 0/1
• BORDER(CONFIG)#ROUTER EIGRP 1
• BORDER(CONFIG-ROUTER)#REDISTRIBUTE STATIC METRIC 10000 100 255 1 1500
• NOW ONLY REMAINS TO ADD IP DEFAULT-NETWORK COMMAND ON BORDER ROUTER
AND A DEFAULT ROUTE WILL BE GENERATED
• BORDER(CONFIG)#IP DEFAULT-NETWORK 192.168.100.0

12. DEFAULT ROUTE IS INJECTED INTO R1’S ROUTING TABLE
• R1#SHOW IP ROUTE
• ... OUTPUT OMITTED ...
• GATEWAY OF LAST RESORT IS 192.168.0.3 TO NETWORK 192.168.100.0
• C 192.168.0.0/24 IS DIRECTLY CONNECTED, FASTETHERNET0/0
• D*EX 192.168.100.0/24 [170/307200] VIA 192.168.0.3, 00:13:51,
FASTETHERNET0/0
• R1#

13. DEFAULT ROUTE WITH NETWORK 0.0.0.0 COMMAND
• WITH THIS METHOD YOU ALSO NEED TO HAVE A DEFAULT ROUTE ON ROUTER THAT
GENERATES DEFAULT ROUTE AND THEN USE NETWORK 0.0.0.0 COMMAND, CHECK
CONFIGURATIONS ON BORDER BELOW
• BORDER(CONFIG)#IP ROUTE 0.0.0.0 0.0.0.0 FASTETHERNET0/1
• BORDER(CONFIG)#ROUTER EIGRP 1
• BORDER(CONFIG-ROUTER)#NETWORK 0.0.0.0

14. • R1#SHOW IP ROUTE
• ... OUTPUT OMITTED ...
• GATEWAY OF LAST RESORT IS 192.168.0.3 TO NETWORK 0.0.0.0
• D 10.0.0.0/8 [90/307200] VIA 192.168.0.3, 00:05:41, FASTETHERNET0/0
• C 192.168.0.0/24 IS DIRECTLY CONNECTED, FASTETHERNET0/0
• D* 0.0.0.0/0 [90/307200] VIA 192.168.0.3, 00:05:41, FASTETHERNET0/0
• R1#
• R1#PING 192.168.100.1
• TYPE ESCAPE SEQUENCE TO ABORT.
• SENDING 5, 100-BYTE ICMP ECHOS TO 192.168.100.1, TIMEOUT IS 2 SECONDS:
• !!!!!
• SUCCESS RATE IS 100 PERCENT (5/5), ROUND-TRIP MIN/AVG/MAX = 20/37/44 MS
• R1#

15. BY USING IP SUMMARY-ADDRESS COMMAND
• AN ALTERNATIVE METHOD TO CONFIGURE A MANUAL SUMMARY ROUTE ON A
INTERFACE WITH SUMMARY ADDRESS 0.0.0.0 AND MASK 0.0.0.0. THEN, ROUTER WILL
SEND A DEFAULT ROUTE ON THAT INTERFACE.
• BORDER(CONFIG)#INTERFACE FASTETHERNET 0/0
• BORDER(CONFIG-IF)#IP SUMMARY-ADDRESS EIGRP 1 0.0.0.0 0.0.0.0
• BORDER(CONFIG)#IP ROUTE 0.0.0.0 0.0.0.0 FASTETHERNET 0/1

16. • R1#SHOW IP ROUTE
• ... OUTPUT OMITTED ...
• GATEWAY OF LAST RESORT IS 192.168.0.3 TO NETWORK 0.0.0.0
• C 192.168.0.0/24 IS DIRECTLY CONNECTED, FASTETHERNET0/0
• D* 0.0.0.0/0 [90/307200] VIA 192.168.0.3, 00:00:51, FASTETHERNET0/0
• R1#
• R1#PING 192.168.100.1
• TYPE ESCAPE SEQUENCE TO ABORT.
• SENDING 5, 100-BYTE ICMP ECHOS TO 192.168.100.1, TIMEOUT IS 2 SECONDS:
• !!!!!
• SUCCESS RATE IS 100 PERCENT (5/5), ROUND-TRIP MIN/AVG/MAX = 20/40/60 MS
• R1#

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