Routing: Algoritma Routing (Dinamis) :

Routing: 1. 2. 3.

Routing Default Routing Statis Routing Dinamis

Algoritma Routing (Dinamis) : 1. Distance Vector Routing 2. Link State Routing

Distance Vector Routing Protocols • Contoh Protokol Routing Distance Vector :  Routing Information Protocol (RIP)

 Interior Gateway Routing Protocol (IGRP)  Enhanced Interior Gateway Routing Protocol (EIGRP)

Distance Vector Routing Protocols • Distance Vector Technology –The Meaning of Distance Vector: • A router using distance vector routing protocols knows 2 things:

Distance to final destination Vector, or direction, traffic should be directed

Distance Vector Routing Protocols Karakteristik Distance Vector : Update Periodik  Tetangga Update Broadcast  Seluruh tabel Routing dimasukkan saat update

Distance Vector Routing Protocols  Routing Protocol Algorithm:

(Algoritma adalah Sebuah prosedur untuk memenuhi sebuah kerja tertentu) Tujuan Algoritma Routing: 1. Mengirim dan menerima Update 2. Mengkalkulasi Jalur terbaik 3. Mendeteksi dan bereaksi terhadap perubahan topologi

Distance Vector Routing Protocols Routing Protocol Characteristics –Kriteria yang digunakan untuk membandingkan protokol routing :

 -Waktu konvergensi  -Skalabilitas  -Penggunaan Resources  -Implementasi dan maintenance

Distance Vector Routing Protocols

Network Discovery • Router initial start up (Cold Starts) -Initial network discovery  Network yang terhubung langsung ditempatkan di tabel routing.

Network Discovery • Tukar Menukar tabel informasi pertama kali – Jika sebuah protokol routing di konfigurasi, maka akan terjadi saling tukar informasi routing

• Update Routing diterima dari router lainnya -Router melakukan memeriksa informasi update jika ada informasi baru -Jika ada informasi baru:

-Metric di update -Informasi baru disimpan ke dalam tabel routing

Network Discovery • Tukar Menukar Informasi Routing – Konvergensi router tercapai apabila

- Seluruh tabel routing pada network tersebut network yang sama. Jika belum tercapai,

berisi informasi

–Router akan terus saling bertukar informasi routing

-Jika tak ada informasi baru ditemukan maka Convergence (konvergensi ) telah reached (tercapai)

Network Discovery • Konvergensi harus dicapai sebelum sebuah network dianggap beroperasi lengkap • Kecepatan pencapaian konvergensi tergantung dari dua kategori yang saling berhubungan - Kecepatan broadcast informasi routing - Kecepatan dalam mengkalkulasi route

Permasalahan pada Distance Vector • Konvergensi yang Lambat • Skalabilitas yang terbatas • Routing Loops

Inconsistent Routing Entries

• Each node maintains the distance from itself to each possible destination network.

Inconsistent Routing Entries (Cont.)

• Slow convergence produces inconsistent routing.

Inconsistent Routing Entries (Cont.)

• Router C concludes that the best path to network 10.4.0.0 is through router B.

Inconsistent Routing Entries (Cont.)

• Router A updates its table to reflect the new but erroneous hop count.

Count to Infinity

• Hop count for network 10.4.0.0 counts to infinity.

Defining a Maximum

• Define a limit on the number of hops to prevent infinite loops.

Routing Loops

• Packets for network 10.4.0.0 bounce (loop) between routers B and C.

Routing Loops • Routing loops adalah kondisi ketika paket dikirimkan secara terus menerus tanpa mencapai tujuannya.

Routing Loops • Routing loops may be caused by: -Incorrectly configured static routes -Incorrectly configured route redistribution -Slow convergence -Incorrectly configured discard routes

• Routing loops can create the following issues -Excess use of bandwidth -CPU resources may be strained -Network convergence is degraded -Routing updates may be lost or not processed in a timely manner

Mengatasi Routing Loops • • • •

Split Horizon Route Poisoning Hold down timer Trigger Update

Split Horizon

• It is never useful to send information about a route back in the direction from which the original information came.

Route Poisoning

• Routers advertise the distance of routes that have gone down to infinity.

Poison Reverse

• Poison reverse overrides split horizon.

Holddown Timers

• The router keeps an entry for the network’s possible down state, allowing time for other routers to recompute for this topology change.

Triggered Updates

• The router sends updates when a change in its routing table occurs.

Routing Protocols Today • Factors used to determine whether to use RIP or EIGRP include -Network size -Compatibility between models of routers -Administrative knowledge