PERN2 LOW LEVEL DESIGN

(Routing Implementation)By:Jawad RazaManager Network & Operationsjraza@hec.gov.pk

Friday 30th August,2013

HEC(khi)

Legend10G Link1G Link

BUITMS(QTA)

USINDH(HYD)

BZU(MLT)

GCUL Uop-OLDKCW

LCWUNCA

PASCUETUVAS

PU-NEW NCOEIMB

FASTUHS

VU

HEC(lhr)

LSELUMS

UOEUOGSUUOAGCU

FAST

CPSP

PNA

KUHU

IBANED

SSUETHEJ

AKUDUHS

UET,KhuzdarLU

QeAMUET

LUMHS SALUSAU

IBA

UOB

CSC

SBKWU

AUPIMS

PU

UETGU

KUUOMCoAE

GIK HU

PMAHEC(Pesh)

IU(BWP)

HEC(ISB)

PUUSTAIOU

NUMLFAST

IIUArid NUST H-12

BU

AU

FJWU

QAU

NDU NUST,RWP

IST

NCPCIIT

PIES

AUF(FSD)

High Level Design

Topology Design

Planning

Core layer

• Level-1: • Three (3) cRA-PoP

routers, located at the major cities of Pakistan

• • Level-2:

• Five (5) sRA-PoP routers, located at the small cities

• Level-3:• Seven (7) LA-PoP router,

to cover the metro cities

InternetServiceProvider

User-B

User-ACampus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

NRENs LinkTEIN3 Network

User-C

Stanford University,

Core layer

1. Level-1: 1. Three (3) cRA-PoP

routers, located at the major cities of Pakistan

2. Level-2:

1. Five (5) sRA-PoP routers, located at the small cities

3. Level-3:1. Seven (7) LA-PoP router,

to cover the metro cities

InternetServiceProvider

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

NRENs LinkTEIN3 Network

Traffic Categories

• A – Internet traffic:• IP Transit Connectivity

• • B – Intranet traffic:

• Connectivity among the PERN2 Campuses

• Intranet Bandwidth should be Separate from Internet Bandwidth

• C – International NREN (R&D) traffic

• For the R&D traffic Bandwidth must be separate from Intranet and Internet

InternetServiceProvider

NRENs ConnectivityTEIN3 Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Stanford (USA)

Routing Basics

IPv4 Addressing Routing & Forwarding Routing Protocols

◦ IGPs◦ EGP

Routing Basic

What does the router do?

Find path & forward packet…… if primary path is not available find alternate path….

Router

?

Routing:◦ Selection of Path in the networks along with which to send network traffic

Forwarding:◦ Moving packets between interfaces according to the “directions”

Routing vs Forwarding

Path derived from information received from a routing protocol Several alternative paths may exist best next hop stored in forwarding table Decisions are updated periodically or as topology changes (event driven) Decisions are based on:

◦ Topology, policies and metrics (hop count, filtering, delay, bandwidth, etc.

IP Routing

Based on destination IP packets

IP Route

R1

R4

R3

R2

10/16 R4

20/8 R630/8 R5

40/8 R30

Packet Destination:10.1.1.1

10/16

40/8

32 bits long address, ◦ Range from 1.0.0.0 to 223.255.255.255

Serves with two principal function i.e Network portion and Host Portion Address & Mask written as

◦ 192.168.1.1 255.255.255.0 or 192.168.1.1/24 Some of the IP addresses are reserved

◦ Private IP Addresses◦ Multicast IP Addresses

IPv4 Address

Interior Gateway Protocols ◦ within a single autonomous system

single network administration unique routing policy make best use of network resources

Exterior Gateway Protocols ◦ among different autonomous systems

independent administrative entities communication between independent network

infrastructures

Routing Protocols IGP & EGP

Collection of networks with same routing policy Single routing protocol Usually under single ownership, trust and administrative control Identified by a unique number

Autonomous System (AS)

AS 100

IGP◦ RIP◦ IS-IS◦ OSPF

EGP◦ BGP

IGP & EGP Protocols

PERN2 Selection of IGPs

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGP

Single network administration

unique routing policy

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGP

Single network administration

unique routing policy

EGP

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGPs1. RIP2.

OSPF3. IS-IS

RIP (Routing Information Protocol)

Routing Information Protocol◦ Two Versions of RIP

RIPv1 RIP v2

Distance Vector Routing Protocol

RIPng (Next Generation) design for IPv6 routing

What is RIP

Routers are advertised as vector of distance and direction.

Direction is represented by next hop address and exit interface.

Whereas Distance uses metrics such as hop count

Updates are performed periodically in a distance vector protocol where all router's routing table is sent to all its neighbors

The cost of reaching a destination is calculated using various route metrics, RIP uses hop count to calculate metric.

Distance Vector Routing

Hop count Limit to 15

RIP eats lots of bandwidth (all broadcast traffic) on large networks

RIP takes 30 – 60 seconds to converge

RIP in large ISP

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGPs1. RIP2.

OSPF3. IS-IS

OSPFOpen Shortest Path First

Most Widely used IGP routing protocol

Link State Protocol

Allow routers to dynamically learn routes from other routers and to advertise routes to other routers.

OSPF

OSPF operation can be divided into three categories

OSPF Operations

Neighbor and Adjacency initialization

LSA Flooding

SPF Calculation

In a link-state protocol, the network can be viewed as a jigsaw puzzle Each jigsaw piece holds one router

Each router creates a packet which represents its own jigsaw piece This packet is called a Link State Advertisement (LSA)

Link State Routing Protocol

LSP for router-B LSP for router-A

to A to B

to E to D

to C to E

to A to B

to A LSP for router E to B

to C to D

LSP for router-D LSP for router-C

These packets are flooded everywhere

Therefore each router receives all pieces of the jigsaw puzzle

Each routers compute SPF algorithm to put the pieces together

Input: all jigsaw puzzle pieces Output: Area or network topology treeShortest Path Tree

All routers exchange all LSAsvia a reliable flooding mechanism Link

OSPF Areas Area is a group of contiguous hosts and networks

Reduces routing traffic Per area topology database Backbone area MUST be contiguous

◦ All other areas must be connected to the backbone

Area 1Area 2

Area 3 Area 4

Area 0Backbone Area

R1R2

R3R4

R5 R6

R7 R8

R9

R10 R11

R12

Support Large Network

Fast Update and Convergence

Support VLSM

Dividing the whole routing domain into different areas

Support Authentication

OSPF Features

OSPF for IPv6

Based on OSPFv2, with enhancements

Distributes IPv6 prefixes

Runs directly over IPv6

Ships-in-the-night with OSPFv2

OSPFv3

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGPs1. RIP2.

OSPF3. IS-IS

ISIS (Intermediate System to Intermediate System)

IS an IGP (Interior Gateway Protocol) scalable only for dynamic routing within a domain

Link State Protocol

IS a dynamic routing protocol based on SPF routing algorithm

IS is “OSI speak” for router

Easily extendable for other routing protocolMainly IPv6

What is ISIS

IS-IS has 2 levels of hierarchy◦ Level-1 (L1)

Neighbors only in the same AREA, and information about its own area

Hierarchy

L1 Adjacencies R1 R2

L1 L1

R3

L1

Embraced by the large tier1 ISPs. Proven to be a very stable and scalable, with

very fast convergence. Encodes the packet(s) in TLV format. Flexible protocol in terms of tuning and easily

extensible to new features (MPLS-TE etc). It runs directly over Layer 2. (next to IP).

Why IS-IS?

InternetServiceProvider

TEIN3Network

User-A

User-B

Campus-A

Campus-B

Isb-PoP

Khi-PoP

Lhr-PoP

IGPs1. RIP2.

OSPF3. IS-IS

Similarities: OSPF and IS-IS are more similar than they are different.

Both are Link State Routing Protocol Both ISIS & OSPF Support Hierarchical Routing Both Support VLSM, CDIR, Authentication, Multiple Paths

ISIS & OSPF Similar Terminologies ◦ OSPFISIS

Host End System (ES) RouterIntermediate System (IS) Link Circuit Packet Protocol Data Unit (PDU Link-State Advertisement (LSA) Link-State PDU (LSP) Area Sub domain (area) Non-backbone area Level-1 area Backbone area Level-2 Sub domain (backbone) Area Border Router (ABR) L1L2 router

ISIS and OSPF

Difference:

ISIS over OSPF

ISIS OSPFGenerally supports a up to 1024 nodes in the same Area

Generally deployed with a much smaller number of nodes (less than 200).

SPF table not refresh periodically. OSPF does so after 30min.

Provide more extensibility , for example ISIS was given new TLVs to Support IPv6.TLVs can also be utilize to carry MPLS TE attributes (ISIS-TE)

OSPF was completely re-written to Support IPv6 (i.e OSPFv3)

ISIS group update into one packet and send them as one LSP, so to increase network efficiency

OSPF produce many LSAs

C I S C O “Which IGP should an ISP choose?

◦ Both OSPF and ISIS use Dijkstra SPF algorithm◦ Exhibit same convergence properties◦ ISIS can runs on data link layer, OSPF runs on IP layer◦ Biggest ISPs tend to use ISIS◦ Main ISIS implementations more tuneable than equivalent OSPF

implementations “

ISIS over OSPF

GEANT2 http://www.geant2.net/server/show/nav.1525 : “The IGP currently used in GÉANT is the ISO IGP IS-IS (Intermediate System to Intermediate System), which provides support for both IPv4 and IPv6”.

CANARIE http://www.canarie.ca/canet4/services/c4_routing_policy.pdf “The Intermediate System-to-Intermediate System (IS-IS) routing protocol is the IGP for CA*net 4, where a single IS-IS Level 2 area is defined. IS-IS was chosen over OSPF mainly for network migration considerations as well as for early release of advanced backbone network feature support by major routing vendors”.

Ufone Pakistan (Largest Telecomm Operator in Pakistan)

China Telecomm (An extra-large State-owned telecom operator in China) CMPaK (Telecomm Operator in Pakistan)

References

IS-IS

ISIS Cost (Core)

Legend10G Link(Optic Fiber)

PSH-HECISB-HEC

LHR-HEC

KHI-HEC

MLT-BZU

QTA-BUITMS

HYD-USINDH

10G Link(Long Haul Fiber)

FSD-AUF

IS-IS enable interface

10

10 10

10 10

10

10

10

10

1010

1010

10

1010

10

10

10

ISIS Core layer

NE40E/80E (PE)

VOIP Service

NE20E (CPE)

Internet Service

VOD,IPTV, Streaming, etc.

International University Service, Webserver, Mailserver, etc.

One interlink ipNAT and one default route

pointing to NE20E

OSPF

• OSPF process Between PoP Router & Access router

• Under different Management

• Easier to Manage for a campus environment

OSPF Design (PoP & Access)

Page 48

GE Optic linkApplications topology (POP Site)

NE20E (CPE) MPLS Backbone

NE40E/80E (PE)

FE Electric link

Internet Service

VOIP Service

VOD,IPTV, Streaming, etc.

International University Service,Webserver, Mailserver, etc.

L2VPN Service

Subinterface10: enable ISIS/MPLS for L2VPNSubinterface20: Internet Subinterface30: NRENSubinterface40: Intranet

CPE:.

One interlink ipNAT and one default

route pointing to NE20E

NMS Servers &Clients.

InternetServiceProvider

TEIN3Network

IS-IS BGP

OSPF

BGP(Border Gateway Protocol)

A Routing protocol used to exchange routing information between different Networks

The Autonomous System is BGP’s fundamental operating unit◦ It is used to uniquely identify networks with a

common routing policy

Border Gateway Protocol

Collection of networks with same routing policy Single routing protocol Usually under single ownership, trust and administrative control Identified by a unique number

Autonomous System (AS)

AS 100

Two ranges◦ 0-65535 (original 16-bit range)◦ 65536-4294967295 (32-bit range - RFC4893)

Usage:◦ 0 and 65535 (reserved)◦ 1-64495 (public Internet)◦ 64496-64511 (documentation - RFC5398)◦ 64512-65534 (private use only)◦ 23456 (represent 32-bit range in 16-bit world)◦ 65536-65551 (documentation - RFC5398)◦ 65552-4294967295 (public Internet)

ASNs are distributed by the Regional Internet Registries◦ They are also available from upstream ISPs who are members of one of the RIRs

The RIRs also have received 1024 32-bit ASNs each◦ Out of 190 allocations, around 50 are visible on the Internet◦ See www.iana.org/assignments/as-numbers

Autonomous Number System (ASN)

Multi-homing with BGP is a way to manage redundant links to multiple ISPs.

Maintaining links to multiple Internet provider (Usually 2 or 3) and using BGP to send routs and receive full routing tables from these providers

Multi-homing

ISP-2 ISP-1

Multi-homed Customer

AS 100

Route ReceivedPrefix announcement

Prefix announcement

Route Received

EBGP & IBGP Implementation

ISP-2

ISP-1

PE

KHI-HEC-P-PE-EGRESS-NE80E

ISB-HEC-P-PE-EGRESS-NE80E

IBGPPEPE

PE

EBGP

EBGP

ISP-2

EBGP

ISP-1

EBGP

PERN2 BGP DESIGN

eBGP p

eerin

g

ISP1ASN-1

ISP2ASN-2

eBGP peering Full R

outin

g fee

d Rece

ived

Full Routing feed Received

Router Receives Full routing table from both ISP’s, and store the best available routes reveries from both these ISPs,

eBGP p

eerin

g

ISP1ASN-1

ISP2ASN-2

eBGP peering

PERN2 Prefixes

P1/24P2/24P3/24P4/24P5/24P6/24P7/24P8/24

Primary Prefixs

P1/24P2/24P3/24P4/24

Primary Prefixs

P5/24P6/24P7/24P8/24

Prepend Prefixs

P5/24 P6/24P7/24P8/24

Prepend Prefixs

P1/24P2/24P3/24P4/24

Prefix'

s Ann

ounce

ment Prefix's Announcement

BGP Policy routing has been applied, AS-PATH Prepend for the load balancing on Incoming traffic

eBGP p

eerin

g

ISP1ASN-1

ISP2ASN-2

PERN2 Prefixes

P1/24P2/24P3/24P4/24P5/24P6/24P7/24P8/24

Primary Prefixs

P1/24P2/24P3/24P4/24

Primary Prefixs

P5/24P6/24P7/24P8/24

Prepend Prefixs

P5/24 P6/24P7/24P8/24

Prepend Prefixs

P1/24P2/24P3/24P4/24

Prefix'

s Ann

ounce

ment

In Case of One link failure, the prefix prepend traffic will be shifted to backup link.

Prepend Prefixs

P5/24 P6/24P7/24P8/24

In Case of Link Failure

eBGP peering

Prefix's Announcement

eBGP is used to learn the Internet Routes and advertised PERN2 IP prefixes on Internet

iBGP then originate connected networks and also pass on prefixes learned from outside the ASN

ISIS has been used as an IGP Protocol on the core network of PERN2

OSPF has been used as an IGP protocol between the core and access network.

Conclusion

Customer Relationship Management (CRM) Service Communicator◦ Generates Tickets◦ http://sc.hec.gov.pk◦ 24/7 Help Line also Available i.e

111-11PERN 051-9040PERN

◦ Complain also can log by email pern2noc@hec.gov.pk

THANKS