Lab 14. RIP Split Horizon
Split horizon adalah suatu metoda untuk menghindari routing loops, mekanismenya dengan menolak mengirim route kembali melalui interface tempat route tersebut diterima.
Tujuan Lab :
- Mempelajari mengapa split horizon harus didisable pada RIP frame relay
Topologi Lab :
Metode Lab :
- Buat seperti topologi di atas
- Konfigurasikan frame relay dengan DLCI sesuai di atas
- Konfigurasikan RIP Routing
- Disable Split Horizon
Verifikasi Lab :
- Periksa apakah IP Loopback Router R2 dapar di Ping dari Router R3 dan sebaliknya
Konfigurasi Router Frame Relay Switch (FRSW)
frame-relay switching
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 2000000
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 102 interface Serial0/1 201
frame-relay route 103 interface Serial0/2 301
!
interface Serial0/1
no ip address
encapsulation frame-relay
clock rate 2000000
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 201 interface Serial0/0 102
!
interface Serial0/2
no ip address
encapsulation frame-relay
clock rate 2000000
frame-relay lmi-type cisco
frame-relay intf-type dce
frame-relay route 301 interface Serial0/0 103
Konfigurasi Router R1
interface Loopback0
ip address 1.1.1.1 255.255.255.255
!
interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 2000000
!
interface Serial0/0.123 multipoint
ip address 123.123.123.1 255.255.255.0
no ip split-horizon
snmp trap link-status
frame-relay map ip 123.123.123.3 103 broadcast
frame-relay map ip 123.123.123.2 102 broadcast
!
router rip
version 2
network 0.0.0.0
no auto-summary
Konfigurasi Router R2
interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface Serial0/0
ip address 123.123.123.2 255.255.255.0
encapsulation frame-relay
clock rate 2000000
frame-relay map ip 123.123.123.1 201 broadcast
frame-relay map ip 123.123.123.3 201
!
router rip
version 2
network 0.0.0.0
no auto-summary
!
Konfigurasi Router R3
interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface Serial0/0
ip address 123.123.123.3 255.255.255.0
encapsulation frame-relay
clock rate 2000000
frame-relay map ip 123.123.123.2 301
frame-relay map ip 123.123.123.1 301 broadcast
!
router rip
version 2
network 0.0.0.0
no auto-summary
!
Cek Mapping, Tabel Routing dan Tes Ping
Router R1
R1#sh frame-relay map
Serial0/0.123 (up): ip 123.123.123.2 dlci 102(0x66,0x1860), static,
broadcast,
CISCO, status defined, active
Serial0/0.123 (up): ip 123.123.123.3 dlci 103(0x67,0x1870), static,
broadcast,
CISCO, status defined, active
R1#sh ip route rip
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/1] via 123.123.123.2, 00:00:15, Serial0/0.123
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/1] via 123.123.123.3, 00:00:12, Serial0/0.123
R1#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/35/92 ms
R1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/44/120 ms
R1#sh ip route rip
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/1] via 123.123.123.2, 00:00:15, Serial0/0.123
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/1] via 123.123.123.3, 00:00:12, Serial0/0.123
R1#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/35/92 ms
R1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/44/120 ms
Router R2
R2#sh frame-relay map
Serial0/0 (up): ip 123.123.123.1 dlci 201(0xC9,0x3090), static,
broadcast,
CISCO, status defined, active
Serial0/0 (up): ip 123.123.123.3 dlci 201(0xC9,0x3090), static,
CISCO, status defined, active
R2#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:13, Serial0/0
> Loopback0 Router R3 tidak muncul
R2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/71/112 ms
R2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
R2#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:13, Serial0/0
> Loopback0 Router R3 tidak muncul
R2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/71/112 ms
R2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router R3
R3#sh frame-relay map
Serial0/0 (up): ip 123.123.123.2 dlci 301(0x12D,0x48D0), static,
CISCO, status defined, active
Serial0/0 (up): ip 123.123.123.1 dlci 301(0x12D,0x48D0), static,
broadcast,
CISCO, status defined, active
R3#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:26, Serial0/0
> Loopback0 Router R2 tidak muncul
R3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/27/72 ms
R3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router R2 tidak dapat ping ke Lo0 Router R3, begitupun sebaliknya. Mengapa? karena tidak terdapat dalam routing tabel, walaupun sudah diadvertise dalam RIP
Cek Split Horizon
Router R1
R1#sh ip int s0/0.123
Serial0/0.123 is up, line protocol is up
Internet address is 123.123.123.1/24
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Multicast reserved groups joined: 224.0.0.9
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
Router R2
R2#sh ip int s0/0 | include Split
Split horizon is disabled
Router R3
R3#sh ip int s0/0 | include Split
Split horizon is disabled
Seperti kita lihat pada Router R1, IP Split Horizon dalam status enable, sehingga mekanisme split horizon menyebabkan Loopback0 Router R2 tidak dikenali oleh Router R3 dan begitupun sebaliknya Loopback0 Router R3 tidak dikenali oleh Router R2.
Menonaktifkan Split Horizon
R1(config)#int s0/0.123
R1(config-subif)#no ip split-horizon
R1(config-subif)#do clear ip route *
Cek kembali tabel routing pada Router R2 dan R3, kemudian tes ping
R2#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:13, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/2] via 123.123.123.3, 00:00:13, Serial0/0
R2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/24/68 ms
R2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/92/164 ms
R3#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:04, Serial0/0
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/2] via 123.123.123.2, 00:00:04, Serial0/0
R3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/42/136 ms
R3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/84/220 ms
Ketika split horizon berstatus enable di sisi R1, maka RIP Routing dari R2 tidak dapat diterima dengan baik pada R3 dan sebaliknya. Setelah split horizon didisable pada interface serial R1, kemudian RIP Route dapat diterima dengan baik di masing-masing router. Split horizon mencegah route yang dikirim ke router lain kembali dikirimkan ke router pengirimnya.
Split horizon tidak menjadi isu bila dikonfigurasikan pada sebuah interface (statusnya disable), namun ketika dikonfigurasikan pada subinterface, maka hal tersebut akan menjadi masalah seperti kasus lab di atas (statusnya enable).
Sumber: id-networkers
Next Lab >> Lab 15. RIP Summary Address
Previous Lab >> Lab 13. RIP Authentication
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:26, Serial0/0
> Loopback0 Router R2 tidak muncul
R3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/27/72 ms
R3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
Router R2 tidak dapat ping ke Lo0 Router R3, begitupun sebaliknya. Mengapa? karena tidak terdapat dalam routing tabel, walaupun sudah diadvertise dalam RIP
Cek Split Horizon
Router R1
R1#sh ip int s0/0.123
Serial0/0.123 is up, line protocol is up
Internet address is 123.123.123.1/24
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Multicast reserved groups joined: 224.0.0.9
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
Router R2
R2#sh ip int s0/0 | include Split
Split horizon is disabled
Router R3
R3#sh ip int s0/0 | include Split
Split horizon is disabled
Seperti kita lihat pada Router R1, IP Split Horizon dalam status enable, sehingga mekanisme split horizon menyebabkan Loopback0 Router R2 tidak dikenali oleh Router R3 dan begitupun sebaliknya Loopback0 Router R3 tidak dikenali oleh Router R2.
Menonaktifkan Split Horizon
R1(config)#int s0/0.123
R1(config-subif)#no ip split-horizon
R1(config-subif)#do clear ip route *
Cek kembali tabel routing pada Router R2 dan R3, kemudian tes ping
R2#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:13, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
R 3.3.3.3 [120/2] via 123.123.123.3, 00:00:13, Serial0/0
R2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/24/68 ms
R2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/92/164 ms
R3#sh ip route rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1] via 123.123.123.1, 00:00:04, Serial0/0
2.0.0.0/32 is subnetted, 1 subnets
R 2.2.2.2 [120/2] via 123.123.123.2, 00:00:04, Serial0/0
R3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/42/136 ms
R3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/84/220 ms
Ketika split horizon berstatus enable di sisi R1, maka RIP Routing dari R2 tidak dapat diterima dengan baik pada R3 dan sebaliknya. Setelah split horizon didisable pada interface serial R1, kemudian RIP Route dapat diterima dengan baik di masing-masing router. Split horizon mencegah route yang dikirim ke router lain kembali dikirimkan ke router pengirimnya.
Split horizon tidak menjadi isu bila dikonfigurasikan pada sebuah interface (statusnya disable), namun ketika dikonfigurasikan pada subinterface, maka hal tersebut akan menjadi masalah seperti kasus lab di atas (statusnya enable).
Sumber: id-networkers
Next Lab >> Lab 15. RIP Summary Address
Previous Lab >> Lab 13. RIP Authentication
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