Routing und Flow Control im Internet der Zukunft Routing and Flow

www3.informatik.uni-wuerzburg.de

Institute of Computer Science

Department of Distributed Systems

Prof. Dr.-Ing. P. Tran-Gia

Routing und Flow Control im Internet der Zukunft

–

Routing and Flow Control in the Future Internet

Michael Menth

2Routing and Flow Control in the Future Internet

Michael Menth

Outline

Two major problems of routing in the Internet

Depletion of available IPv4 addresses

– Solution: IPv6

– Interworking IPv6 – IPv4

– Deployment

Growth of the routing tables in the DFZ

– Causes

– Solutions: principles of future Internet routing

Flow control in the future Internet

Pre-congestion notification (PCN)

Admission control and flow termination

Conclusion


Michael Menth

Depletion of Free IPv4 Address Pool

IANA (Internet Assigned Numbers Authority)

Projected depletion of unallocated IPv4 address pool: 28.01.2011

IPv4

Address format: 4 bytes ~ 4.3×109 addresses

8,4 addresses per km2 earth surface

Structure: 132.187.12.123

IPv6

Address format: 16 bytes ~ 3.4×1038 addresses

6,67 × 1017 addresses per mm2 earth surface

Structure: 2001:DB8:0:0:8:800:200C:417A

Prefix notation: 132.187/16: 16 bits prefix (~ address block)

Interworking problems

IPv6 addresses unknown to legacy applications, hosts, and routers

Dual-stack (IPv4 and IPv6) required


Michael Menth

IPv4 – IPv6 Interworking Principles: Tunneling

IPv6 traffic tunneled through IPv4 networks

IPv4 IPv6IPv6

B Data

AB

B DataB DataY

X Y


Michael Menth

IPv4 – IPv6 Interworking Principles: Address Conversion

Conversion between IPv4 and IPv6 addresses

132.187.12.123

0:0:0:0:0:ffff:Hex(132.187.12.123)

Applicable only to actual IPv4 addresses

Conversion between IPv4 headers and IPv6 headers

Stateless IP/ICMP translation (SIIT)

IPv6IPv4 IPv4


Michael Menth

Problem

Real IPv6 address not

convertible into IPv4 address

Network address port translation (NAPT)

IPv4 border router converts

– From IPv6 address and port

– Into other IPv4 address and port and back

Example

IPv4 – IPv6 Interworking Principles: NAPT

IPv6 IPv4

NAPT

[A]:1234 [C]:80

[C]:80 [A]:1234

B:5678 C:80

C:80 B:5678

NAPTIPv6 IPv4

[A]:1234 B:5678src dst src dst

Request

Response


Michael Menth

Planned and Actual Deployment of IPv6

Observation

IPv6 hardly adopted

Limited reachability for early

adopters

Source: presentation by G.

Huston and G. Michalson

(APNIC) at RIPE 56 in Berlin,

May 2008

Other partial solution to IPv4 address

depletion

Private networks behind NATs

10/8, 172.16/12, 192.168/16

Planned deployment of IPv6 Actual deployment of IPv6


Michael Menth

IPv4 Outage Experiment at IETF71

IPv4 outage experiment at IETF71 in Philadelphia

(13.03.2008)

IPv6 Internet is only a very small fraction of IPv4

Internet

Most portals do not offer services over IPv6


Michael Menth

The Internet: a Network of Networks

Tier 1 ISP

Tier 1 ISP

Tier 1 ISP

NAP

Tier-2 ISPTier-2 ISP

Tier-2 ISP Tier-2 ISP

Tier-2 ISP

local

ISPlocal

ISP

local

ISP

local

ISP

local

ISP Tier 3

ISP

local

ISP

local

ISP

local

ISP


Michael Menth

Basic BGP Information

BGP information

132.187.0/20 AS-Path: AS338, AS20978

132.187.16/20 AS-Path: AS574, AS231, AS339, AS448

132.187.20/22 AS-Path: AS574, AS1079, AS2098, AS3172

…


Michael Menth

Problem 2: Growth of Routing Table Sizes in the DFZ

IPv4 FIB entries from 01.07.1988 – 16.05.08 (AS2)


Michael Menth

Causes for Increasing FIB Sizes in DFZ (1)

Provider independent addressing

Longest prefix match

Maximum length of propagated prefixes: /24

Provider A Provider B

85.178.0.0/16

85.178.4.0/23

96.103.0.0/16

85.178.4.0/23

DFZ

x


Michael Menth


Multihoming


85.178.0.0/16

85.178.4.0/23

96.103.0.0/16

85.178.4.0/23

DFZ

85.178.4.0/23


Michael Menth


Traffic engineering


85.178.0.0/16

85.178.4.0/23

96.103.0.0/16

85.178.4.0/23

DFZ

85.178.5.0/24 85.178.6.0/24

Incoming

VoIP

Incoming

data

85.178.4.0/23


Michael Menth


Countermeasure against prefix hijacking

Announcement of longer prefixes than necessary

E.g. YouTube prefix hijacking incident by Pakistan Telecom (24.02.08)

Source: RIPE56

AS36561

Pakistan

Telecom

AS17557

208.65.152.0/22 208.65.153.0/24

YouTube

AS3491


Michael Menth

Solution 1: Tweaking the Current Interdomain Routing (1)

Aggregation proxies

Core router-integrated overlay

(CRIO)

The aggregation proxy

announces a short prefix

instead of many long

prefixes.

Packets addressed to

the long prefixes are

routable in the DFZ

They are forwarded to

the aggregation proxy

which tunnels them to

their destination

network.

X.Y.0/24 X.Y.1/24 X.Y.2/24 X.Y.3/24

X.Y.0/22

Statically

configured

tunnels

X.Y.0/22

X.Y.0/22X.Y.0/22

Aggregation

proxy announces

short prefixes


Michael Menth

Solution 1: Tweaking the Current Interdomain Routing (2)

Retain long prefixes and provide

lookup system for direct tunnels

Tunneling route reduction

protocol (TRRP)

Some long prefixes are not

announced to BGP, therefore,

they are not routable in the DFZ.

The lookup system provides a

router for them in the destination

AS such that corresponding

packets can be tunneled,

decapsulated, and forwarded

from there to their destination via

intradomain routing.

X.Y.Z/24

Lookup system

for non-routable

addresses

X.Y

.Z/2

4

Border router

with routable

address


Michael Menth

Solution 2: Locator/Identifier Split

Separation of IP addresses

Identifier

Locator

Mapping function

Identifier locator

Objective

Limit growth of routing tables

Open issues

Mapping system

Exact implementation of Loc/ID

BProvider X

Provider Y

A

Locator(B)Data B

Mapping

service


Michael Menth

Incremental Deployment of Loc/ID for the Internet

Locator ID separation protocol

(LISP)

Cisco‘s proposal within RRG

of IRTF

Local

routing

domain

Gateways

Global

routing

domain

Mapping service

supported by

local caches

12

34

A

B

C

DIdentifiers

Locators

Communication 1 4:

1 sends packet with address 4 to A,

A sends packet with address D4 to D,

D sends packet with address 4 to 4.


Michael Menth

Interworking between the Legacy and the Future Internet

Global routing

domain and

legacy Internet

Local

routing

domain

Proxy

gateway

GatewayLegacy

node

1

AB

Communication 1 B:

1 sends packet with address B to A,

A sends packet with address B to B.

Communication B 1:

B sends packet with address 1 to C,

C sends packet with address A1 to A,

A sends packet with address 1 to 1.

C

Mapping service

supported by

local caches


Michael Menth

Clean Slate Approach for Loc/ID

Identifier (2)

Local locator (LL(2)=b)

Local mapping service

Local

mapping

service

b

2

Data

ID=2

LL(2)=b

a

1


Michael Menth

LL=b

Clean Slate Approach for Loc/ID

Global locator (GL(3)=C)

Global mapping service

LL=cGlobal

mapping

service

Data

ID=3

GL(3)=C

LL for next

jump to C

added using

local routing

tablesData

ID=3

LL(3)=f added

by ingress node

using local

mapping service

b c d e

A B C

Identifier (2)

Local locator (LL(2)=b)

Local mapping service

f

3

Local

mapping

service

a

1

LL=dLL=eLL(3)=f


Michael Menth

Solutions for Improved Scalability

Locator ID separation protocol LISP

Different mapping implementations

Distributed hash table LISP-DHT

Alternative, logical topology LISP-ALT

Content overlay network service LISP-CONS

A not-so-novel EID to RLOC database LISP-NERD

A practical tunneling architecture eFIT-APT

Six/One Router with DNS-based resolution system Six/One

Dynamic internetworking architecture DYNA

Tunneling route reduction protocol TRRP

Internet vastly improved plumbing Ivip

Host identity protocol architecture HIP

Global, site, and end-system address elements GSE

Node identity interworking architecture

Hierarchical routing architecture HRA

New inter-domain routing architecture NIRA

IP with virtual link extension IPvLX

Core router-integrated overlay CRIO

Geographically informed inter-domain routing GIRO

On Compact Routing for the Internet

…


Michael Menth

Pre-Congestion Notification (PCN) –

Flow Control for the Future Internet

Simple support for quality of service (QoS)

No per-flow states inside a network

Admission control

Proactive: keep traffic load low to avoid congestion

High priority transport only for explicitly admitted flows

Block further flows if traffic load is already high

Flow termination

Terminates some admitted flows

Only for exceptional cases

Reactive: reduce traffic load if it is too high due to an accicent


Michael Menth

0

Pre-congestion

type

Impact on

AC and FT

No pre-

congestion

Admissible

rate AR(l)

Admit new flows

PCN rate

r(l)

on link l

AR-pre-

congestionBlock new flows

Supportable

rate SR(l)

SR-pre-

congestion

Block new flows

Terminate someadmitted flows

Pre-Congestion Notification (PCN) – Concept


Michael Menth

PCN Domain

RSVPCapacity

Overprovisioning

Source Destination

End-to-end

flow

PCN ingress

node

PCN egress

node

Router with signalling

functionality

Router with metering &

marking functionalityMMS

S/MM

MM

S

End-to-end

resource

signalling

S/MM

S

S

Edge-to-Edge Pre-Congestion Notification (PCN)


Michael Menth

PCN DomainSource

End-to-end

flow

Router with metering &

marking functionality

Destination

MM

MM

MM

MM

MMMM

MM

End-to-End Pre-Congestion Notification (PCN)


Michael Menth

Conclusion

Pre-congestion notification (PCN)

Packet marking

Admission control

Flow termination

Edge-to-edge and end-to-end PCN

Two major problems in today’s routing

Depletion of available IPv4 address pool

Growth of routing tables

IPv6

Interworking methods with IPv4

No incentive for early adopters

Hardly used

Loc/ID split

Promising design principle for routing scalability

Incremental deployment e.g. LISP

Clean slate Loc/ID

What’s routing like in the Internet in 2020?

Documents

Routing und Flow Control im Internet der Zukunft Routing and Flow