EIGRP na Frame Relay mrezi, split-horizon problem

[ dragansar @ 12.08.2012. 16:29 ] @

Napravio sam jedan Lab u GNS3, tj vjezba u kojoj se pokazuje kako split-horizon u NBMA mrezi moze da prestavlja problem kod EIGRP-a (slika ispod)
Mreza izmedju svih rutera je multipoint, da bi se ustedile adrese.
Kreirani su subinterfejsi na serial 0/0 svakog od rutera

Sve je podeseno kako treba i pingovi sa HQ do EAST i WEST rutera su ok, sada poenta Lab-a je bila da pokaze da ruteri EAST i WEST ne mogu da razmjene ruting tabele zbog split-horizon pravila na ruteru HQ i trebalo bi na njemu iskljuciti split-horizon na subinterfejsu koji ide prema Frame Relay-u

Code:
no ip split-horizon eigrp 25

Kada to uradim, npr ruter EAST dobije rute od rutera WEST (sto naravno nije mogao dok split-horizon nije iskljucen na HQ ruteru)

Citat:

EAST#show ip route
Gateway of last resort is not set
172.16.0.0/29 is subnetted, 1 subnets
C 172.16.124.0 is directly connected, Serial0/0.10
10.0.0.0/24 is subnetted, 3 subnets
D 10.3.1.0 [90/2809856] via 172.16.124.1, 00:26:02, Serial0/0.10
C 10.2.1.0 is directly connected, Loopback1
D 10.1.1.0 [90/2297856] via 172.16.124.1, 00:27:06, Serial0/0.10

Ali problem u svemu tome je sto ja ne mogu sa rutera EAST da pingam 10.3.1.1 (sto je loopback interface na WEST ruteru)

Citat:

EAST#ping 10.3.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.3.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

A sa rutera HQ mogu:

Citat:

HQ#ping 10.3.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.3.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/20/48 ms

Probao sam sa c2600,c3600 i c3700 ruterima, ali isto se desava...i predpostavljam da je neki problem u konfiguraciji koji ja ne mogu da nadjem...ako neko ima ideju sta bi mogao da bude problem, bio bi mu zahvalan :)
Evo i konfigracije:

Citat:

HQ#show run
Building configuration...
Current configuration : 1542 bytes
!
version 12.4
interface Loopback1
ip address 10.1.1.1 255.255.255.0
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 2000000
!
interface Serial0/0.10 multipoint
ip address 172.16.124.1 255.255.255.248
no ip split-horizon eigrp 25
snmp trap link-status
frame-relay map ip 172.16.124.3 103 broadcast
frame-relay map ip 172.16.124.2 102 broadcast
!
router eigrp 25
network 10.1.0.0 0.0.255.255
network 172.16.0.0
no auto-summary

Citat:

WEST#show run
Building configuration...
Current configuration : 1467 bytes
!
version 12.4
interface Loopback1
ip address 10.3.1.1 255.255.255.0
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 2000000
!
interface Serial0/0.10 multipoint
ip address 172.16.124.3 255.255.255.248
snmp trap link-status
frame-relay map ip 172.16.124.1 301 broadcast
!
router eigrp 25
network 10.3.0.0 0.0.255.255
network 172.16.0.0
no auto-summary

Citat:

EAST#show run
Building configuration...
Current configuration : 1467 bytes
!
version 12.4
!
interface Loopback1
ip address 10.2.1.1 255.255.255.0
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 2000000
!
interface Serial0/0.10 multipoint
ip address 172.16.124.2 255.255.255.248
snmp trap link-status
frame-relay map ip 172.16.124.1 201 broadcast
!
router eigrp 25
network 10.2.0.0 0.0.255.255
network 172.16.0.0
no auto-summary

[ pajaja @ 12.08.2012. 18:58 ] @

Pozdrav,

ukratko problem ti pravi nedostatak L3 - L2 mapiranja u FR.
Recimo ako pokusas da pingujes lo1 interfejs WEST rutera sa EAST-a (kao sto si naveo u primeru):
1. EAST salje icmp request sa destinacionom ip adresom 10.3.1.1. Obzirom da se po ruting tabeli do te mreze dolasi preko 172.16.124.1, request se salje ka HQ sa s=172.16.124.2 (adresa s0/0.10 interfejsa, sto je bitno za kasnije).
2. HQ prosledjuje taj request do WEST-a.
3. WEST bi trebalo da odgovori na request koji je dosao sa 172.16.124.2 (s0/0.10 EAST rutera). Obzirom da nema mapiranje za tu adresu enkapsuliranje ce da fejluje.

Ovo mozes da proveris ako ukljucis debug ip packet. Ili mozes da probas da pingujes direktno sa lo1 interfesja i da vidis da li ce da uspe:
ping 10.3.1.1 source lo1.

Resenje za ovo je da dodas u frame-relay map IP adrese na oba spoke-a.

_{[Ovu poruku je menjao pajaja dana 12.08.2012. u 20:10 GMT+1]}