I P addressing Design in Practice Design in Practice I P addressing - - PowerPoint PPT Presentation

APRICOT 2006 at Perth Western Australia APRICOT 2006 at Perth Western Australia

I P addressing I P addressing Design in Practice Design in Practice

Akinori MAEMURA < maem@maem.org> Masataka MAWATARI < mawatari@dti.ad.jp> Kiyoteru I SHI HARA < ki-ishihara@kddi.com>

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APRI COT 2006 APRI COT 2006

What we will talk here from now on What we will talk here from now on

• I P Address

I P Addressing ing is one of the components is one of the components of

• f

network network design design

– I t'

's basic to networking, but really important, and not easy

– – K

Know now -

• how is not

how is not shared shared enough, enough, is it? is it?

Here will be presented about – – Practical and current I Pv4 Addressing

Practical and current I Pv4 Addressing

– – I Pv6

I Pv6 Addressing in comparison with I Pv4 Addressing in comparison with I Pv4

I Pv4 I Pv4 Addressing Addressing

which we should have been familiar with which we should have been familiar with… …

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Addressing Plan is like Addressing Plan is like… …

• Segment and reserve address block for

Segment and reserve address block for several attributes several attributes

• by

by link category link category (user address (user address pool pool, backbone , backbone link, loopback addresses link, loopback addresses … …etc) etc)

• by service (broadband, dialup

by service (broadband, dialup … …etc) etc)

• by

by geographical/ topological area geographical/ topological area

BackBone BackBone

/ 15 / 15

/ 17 / 17 / 18 / 18 / 18 / 18 / 18 / 18 / 17 / 17

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But reality is But reality is… …

• Addressing plan needs to be fit as increase of users

Addressing plan needs to be fit as increase of users and services and services

– – Not easy to operate as planned.

Not easy to operate as planned.

– – Reality is often very different from the assumption

Reality is often very different from the assumption

• Not easy to change design while operating.

Not easy to change design while operating.

– – We often have very little spare I P address for change

We often have very little spare I P address for change

• perations
• perations
• I P address management starts getting disordered

I P address management starts getting disordered

• An unnecessary loss is generated.

An unnecessary loss is generated.

– – I t gets more trouble some to make sure routing works

I t gets more trouble some to make sure routing works fine fine. .

– – Configuring ACL becomes

Configuring ACL becomes more more difficult. difficult.

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Reduce the present problem Reduce the present problem. .

Renumbering -> Aggregation

/ 16 / 16 / 18 / 18 / 18 / 18 / 19 / 19 / 19 / 19 / 19 / 19 / 19 / 19

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How we can do that? How we can do that?

• Revisiting the addressing plan

Revisiting the addressing plan

– – Situations differs by each xSPs

Situations differs by each xSPs

• Consumer I SP

Consumer I SP

– – The biggest

The biggest block blocks s are are assigned for assigned for the client address pool the client address pool

• iDC

iDC

– – Fixed address

Fixed address or address blocks

• r address blocks is assigned

is assigned to to customers. customers.

• Leased Line Service

Leased Line Service

– – Various size of address block are connected to Access

Various size of address block are connected to Access Routers Routers

– – The

The later to fix it, the more difficult to later to fix it, the more difficult to improve improve the the

• rder
• rder
• The availability of I P address

The availability of I P address is is always changing. always changing.

• The situation of service

The situation of service is is always changing, too. always changing, too.

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One of methods One of methods… …

• I nitial Condition

I nitial Condition

/ 26 / 26

Access Provider's Access Provider's Router Router I SP's Router I SP's Router

route * * * .* * * .1.0/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .1.64/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .1.128/ 26 next-hop * * * .* * * .* * * .* * *

Broadband Broadband Access Servers Access Servers

/ 26 / 26 / 26 / 26

Pool Pool Address Address Blocks Blocks static routes static routes

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One of methods One of methods… …(cont.) (cont.)

• Users

Users increasing increasing… …

/ 26+ / 26 / 26+ / 26 / 26+ / 26 / 26+ / 26 / 26+ / 26 / 26+ / 26

route * * * .* * * .1.0/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .1.64/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .1.128/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .1.192/ 26 next-hop * * * .* * * .* * * .* * * route * * * .* * * .2.0/ 26 next-hop * * * .* * * .* * * .* * *

I SP's Router I SP's Router Broadband Broadband Access Servers Access Servers When static routes increases, When static routes increases, external routes increases too external routes increases too… … Add / 26 Add / 26 for pool for pool address address blocks. blocks. Access Provider's Access Provider's Router Router

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One of methods One of methods… …(cont.) (cont.)

• Renumbering!!

Renumbering!!

/ 24 / 24

route * * * .* * * .10.0/ 24 next-hop * * * .* * * .* * * .* * * route * * * .* * * .11.0/ 24 next-hop * * * .* * * .* * * .* * * route * * * .* * * .12.0/ 24 next-hop * * * .* * * .* * * .* * *

I SP's Router I SP's Router Broadband Broadband Access Servers Access Servers Static routes are getting Static routes are getting simple!!! simple!!! / 24 / 24 / 24 / 24 Pool Pool Address Address Blocks are Blocks are getting getting simple!!! simple!!! Access Provider's Access Provider's Router Router

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To change the address plan To change the address plan… …

Renumber, defragment and aggregate!! Renumbering is painful, but…

– Together with other maintenances

• Redundant network configuration will help easier

maintenance – I t's still very good to execute renumbering little by little.

• We can sometimes have a sufficient margin for

We can sometimes have a sufficient margin for

• renumbering. Keep track of amount of available I P
• renumbering. Keep track of amount of available I P

address! address!

• Day

Day-

• to

to-

• day checks will work for planning tiny

day checks will work for planning tiny renumbering renumbering – I t will result in reducing the division loss of I P address.

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Summary so far Summary so far

• Your I Pv4 network is already rather old.

Your I Pv4 network is already rather old.

– – I t's necessary to review the I P address

I t's necessary to review the I P address design design

• Clues

Clues for the improvement may come out for the improvement may come out although it is still not found although it is still not found. .

– – You still need to keep

You still need to keep operati

• perating

ng your your I Pv4 I Pv4 network. network.

• I Pv6 is coming ! I t is being as troublesome

I Pv6 is coming ! I t is being as troublesome as I Pv4 is now! as I Pv4 is now!

– – T

Think about I Pv6 addressing hink about I Pv6 addressing now, and the now, and the trouble will be less! trouble will be less!

– – Don

Don' 't repeat the t repeat the same same mistake as mistake as I Pv4. I Pv4.

Consider Considering ing I Pv6 I Pv6

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The way we consider about I Pv6 addressing The way we consider about I Pv6 addressing

Only dual stuck network is to be focused on

• Do we need any special consideration on

Do we need any special consideration on I Pv4 I Pv4 addressing when I Pv6 is added on the network? addressing when I Pv6 is added on the network?

• The method for transition of I Pv6 which you

The method for transition of I Pv6 which you suppose suppose

– – First, w

First, w hile hile considering I Pv6 considering I Pv6 transition transition, , improvement of I Pv4 improvement of I Pv4 network network

– – Secondly,

Secondly, I ntroduction for I Pv6 I ntroduction for I Pv6

• We would like to examine whether consideration

We would like to examine whether consideration (1) (1) is is necessary necessary

I Pv4( I Pv4( now now ) ) I Pv4( I Pv4( improvement improvement) ) I Pv4/ I Pv6 I Pv4/ I Pv6

Care for Care for I Pv6 I Pv6 introduction introduction I s necessary? I s necessary? Which items we should care for? Which items we should care for?

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I tems to be considered I tems to be considered

• Addressing

Addressing

– – Link

Links s

• Point

Point-

• to

to-

• Point

Point Link Link

• LAN

LAN segment segment

– – Logical interface

Logical interfaces s

• Area

Area segmentation segmentation of address block

• f address block
• Router I D

Router I D

• Renumbering

Renumbering

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Addressing Addressing

• Point

Point-

• to

to-

• Point

Point Link

Links s

– – / 64

/ 64 – – as one segment as one segment

– – / 126

/ 126 – – just like as / 30 in case of I Pv4, just like as / 30 in case of I Pv4,

– – / 127

/ 127 – – was said okay originally, but was said okay originally, but… …

• RFC3627

RFC3627 -

• Use of / 127 Prefix Length Between Routers

Use of / 127 Prefix Length Between Routers Considered Harmful Considered Harmful

– – or u

• r unnumbered

nnumbered

• LAN

LAN segment

segments s

– – Don

Don‘ ‘t think! I t is definitely / 64! t think! I t is definitely / 64!

– – 2^ 64 hosts

2^ 64 hosts can be connected (theoretically can be connected (theoretically ☺ ☺ ) )

• we do

we don n' 't need to care about the number of hosts! t need to care about the number of hosts!

• Loopback address

Loopback address

• / 64

/ 64（ （wasting? yes) wasting? yes) or / 128

• r / 128

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Area Area

• fixed size block can be

fixed size block can be allocated to every area allocated to every area

– – For example / 40 for an area

For example / 40 for an area

• 256

256 PoPs PoPs, with 2^ 16 LAN segment each, , with 2^ 16 LAN segment each, … … don don’ ’ t think about the number of t think about the number of hosts! hosts!

• No consideration needed for block size

No consideration needed for block size to be allocated to be allocated

• Network center level

Network center level

– – East/ West Japan

East/ West Japan

– – District, etc.

District, etc.

• Prefecture level,

Prefecture level, Central Central PoP PoP level, level, etc. etc.

– – I mplication to the segmentation of

I mplication to the segmentation of I Pv4? I Pv4?

• Much

Much much much easier than I Pv4. Forget easier than I Pv4. Forget about that! about that!

/ / 40 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 40 / 48 / 48 / 48 / 48

Network Center

/ / 56 56 / / 56 56

GC

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Consideration Consideration on dual stack network

• n dual stack network
• To embed I Pv4 numbers to an I Pv6 address

To embed I Pv4 numbers to an I Pv6 address 19 192 2 2 2 2 22 22 2 I Pv4 I Pv4

(Likely) Host I D on a (Likely) Host I D on a single segment single segment

I Pv6 I Pv6 / 32 prefix / 32 prefix

Host I D on a single segment Host I D on a single segment

2001 : 0D88 2001 : 0D88

２ ２ ０ ２ ０ ２

64bit 64bit

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Request For Comment Request For Comments s

• While

While operating I Pv4 addressing,

• perating I Pv4 addressing, do you have any

do you have any points that points that you pay attention and you have you pay attention and you have devised? devised?

– – The Point of caution and device in case of renumbering

The Point of caution and device in case of renumbering

– – The Point of caution and device in case of managing I Pv4

The Point of caution and device in case of managing I Pv4 addressing addressing

• At the time of I Pv6 introduction, the influence to

At the time of I Pv6 introduction, the influence to addressing and the like of the I Pv4 and addressing and the like of the I Pv4 and consideration point consideration point does not does not seem seem so so many many. .

– – First, do we have to consider

First, do we have to consider this kind of consideration? this kind of consideration?

– – The influence and consideration point is not many

The influence and consideration point is not many. I s it . I s it right? right?

– – What items we should consider?

What items we should consider?