4 byte as number workshop material

4-Byte AS Number Workshop

2009.11.18 2

Agenda

• 4-byte ASN recap• Workshop environment introduction

– IOS Route-Reflector

– IOS Confederation

– JUNOS Route-Reflector

– JUNOS Confederation

• 4-byte ASN in a 2-byte ASN BGP domain• Add 4-byte ASN ready router in a BGP domain• 4-byte ASN BGP policy discussion• Q&A

2009.11.18 3

4-byte ASN recap

• Changes in BGP 4-byte AS:– New BGP capability advertisement

• Capability code: 65• Capability length: 4

– Attribute update• AS_PATH attribute carry 4 byte AS• AGGREGATOR attribute carry 4 byte AS

– New attribute• Add AS4_PATH attribute

– optional, transitive

– Construct from AS_PATH attribute by 4-byte AS enabled router when face to 2-byte AS only router

• Add AS4_AGGREGATOR attribute– optional, transitive

– Construct from AGGREGATOR attribute by 4-byte AS enabled router when face to 2-byte AS only router

2009.11.18 4

4-byte ASN recap

• Limitations:– NEW BGP speaker need a 2-byte AS to peer with the OLD BGP

speaker.• No-mappable 4-byte AS can use “23456” as 2-byte AS

– AS4_PATH is not compatible with:• AS_CONFED_SEQUENCE• AS_CONFED_SET• Must use mappable 4 byte member ASN during the migration

– i.e. 0.64512 ~ 0.65535

• Other considerations– BGP community handling

• Current AS encoding method in BGP community should be updated• ref: draft-rekhter-as4octet-ext-community-03.txt

– Netflow statistics• Netflow version 9 support 4-byte AS number

2009.11.18 5

4-byte ASN recap

» From “4-Byte AS Numbers, The view from the Old BGP world, p21” by Geoff Huston, APNIC

2009.11.18 6

• AS4_PATH example– 193.5.68.0/23

– Attribute Type/Length/Value• Attribute Type (2 octets)

– 0xe0 => optional, transitive– 0x11 => AS4_PATH (TYPE CODE 17)

• Attribute Length (Variable)• AS Path Segments (Variable), which includes

– Segment Type (1 octet)» 0x02 => AS Sequence

– Segment Length (1 octet)» 0x03 => AS numbers in the AS Sequence

– Value (Variable)» 0x00 00 1a ae => 6830 (The AS who generated the

AS4_PATH)

» 0x00 00 22 36 => 8758

» 0x00 03 00 0d => 3.13

4-byte ASN recap

2009.11.18 7

• AS4_PATH example– 195.47.195.0/24


– 0xe0 => optional, transitive

– 0x11 => AS4_PATH (TYPE CODE 17)



– Segment Length (1 octet)» 0x01 => AS numbers in the AS Sequence

– Value (Variable)» 0x00 03 00 10 => 3.16 (The AS who generated the

AS4_PATH)

4-byte ASN recap

2009.11.18 8

• AS4_PATH example– 2001:7fb:ff00::/48


– 0xe0 => optional, transitive– 0x11 => AS4_PATH (TYPE CODE 17)



– Segment Length (1 octet) » 0x03 => AS numbers in the AS Sequence

– Value (Variable)» 0x00 00 04 65 => 1125 (The AS who generated the

AS4_PATH)

» 0x00 03 00 05 => 3.5

» 0x00 00 31 6e => 12654

4-byte ASN recap

2009.11.18 9


4-byte ASN recap

2009.11.18 10


4-byte ASN recap

2009.11.18 11

4-byte ASN recap

• ASDOT– Split the ASN into two 16bits numbers

– ex. 65600 is 1.64 in 2-byte representation• 65600 is “65536*1 + 64”

– Difficult to handle in regular expressions

• ASPLAIN– Just like regular 2-byte AS, but extending to 32 bits

– ex. 65600

• ASPLAIN and ASDOT in the workshop– AS66000 -> AS 1.464

– AS67000 -> AS 1.1464

– AS68000 -> AS 1.2464

– AS69000 -> AS 1.3464

2009.11.18 12

Workshop environment introduction

4-Byte AS Transit ISP/IXISP

customer

Regular ISP

2-Byte AS Transit ISP/IX

ISP customer

ISP customer

Regular ISP

ISP customer

ISP customer

ISP customer

2009.11.18 13

Workshop environment introduction – IOS Route-Reflector

AS69000AS69000AS100AS100

AS101AS101

AS68101AS68101AS67101AS67101AS66101AS66101

F1/0

FE1/0 FE1/1FE1/0 FE1/0

eBG

PeB

GP

iBG

P

R#R# ： 2-byte available only

R#R#： 4-byte available



Login: guestPassword: guest

enable: admin


enable: admin

Transit Interface IP10.100.AS#.R#/1610.69.AS#.R#/16

ISP Interface IP10.AS#.R#R#.R#/24

ISP Loopback IP10.AS#.0.R#/32




172.101.6.0/24172.101.66.0/24 172.101.7.0/24

172.101.8.0/24172.101.68.0/24

<- 172.101.67.0/24 172.101.69.0/24 ->

F1/0

2.2/16 4.4/16

R2 R4F1/1F1/1

R1

R3

R2

R4

R5

R6 R7 R8

F1/0F2/0 F2/0

F1/1

F2/1

F2/0

F2/1F1/0 F1/1

F2/1F2/0F1/0

F1/1F1/1

F1/0

F2/1 F2/0F2/1

10.101/16

10.169/24

2009.11.18 14

Workshop environment introduction – IOS Confederation

AS69000AS69000AS100AS100

AS102AS102

AS68102AS68102AS67102AS67102AS66102AS66102

F1/0

FE1/0 FE1/1FE1/0 FE1/0

eBG

PeB

GP

iBG

P






enable: admin


enable: admin







172.102.6.0/24172.102.66.0/24 172.102.7.0/24

172.102.8.0/24172.102.68.0/24

<- 172.102.67.0/24 172.102.69.0/24 ->

F1/0

2.2/16 4.4/16

R2 R4F1/1F1/1

R1

R3

R4

R5

R6 R7 R8

F1/0F2/0 F2/0

F1/1

F2/1

F2/0

F2/1

F1/0

F1/1F1/1

F1/0

F2/1 F2/0F2/1

10.102/16

10.169/24

AS65102AS65102 AS65112AS65112

eBGP

eBGP

2009.11.18 15

Workshop environment introduction – JUNOS Route-Reflector

AS69000AS69000AS200AS200

AS201AS201

AS68201AS68201AS67201AS67201AS66201AS66201

fxp5.30 fxp5.30

fxp3.30

fxp4.30

fxp5.10 fxp5.10

fxp3.30

fxp4.30

fxp3.10 fxp6.10fxp6.10

fxp5.20

fxp4.10

fxp3.20fxp4.20 fxp5.20

fxp6.20 fxp6.20

fxp5.30 fxp3.10

fxp5.30 fxp4.10

fxp7.10

fxp7.10

fxp4.20

fxp3.20

eBG

PeB

GP

iBG

P

172.201.6.0/24172.201.66.0/24 172.201.7.0/24

172.201.8.0/24172.201.68.0/24

<- 172.201.67.0/24 172.201.69.0/24 ->





10.201/16

Login: admin#Password: Admin#Login: guest#Password: Guest#








2009.11.18 16

Workshop environment introduction – JUNOS Confederation

AS69000AS69000AS200AS200

AS202AS202

fxp5.30 fxp5.30

fxp3.30

fxp4.30

fxp5.10 fxp5.10

fxp3.30

fxp4.30

fxp3.10 fxp3.40

fxp4.10 fxp4.40

fxp6.20 fxp6.20

fxp5.30 fxp3.10fxp7.10 fxp4.20

eBG

PeB

GP

iBG

P

eBGP

eBGP

AS65202AS65202 AS65222AS65222

AS68202AS68202AS67202AS67202AS66202AS66202

fxp5.30 fxp4.10fxp7.10 fxp3.20

172.202.6.0/24172.202.66.0/24 172.202.7.0/24

172.202.8.0/24172.202.68.0/24

<- 172.202.67.0/24 172.202.69.0/24 ->





10.202/16









2009.11.18 17


• Connect to terminal server– Download SSH client (ex. Putty)

– Open a ssh session to 140.122.61.3 or 140.122.61.4• Login ID/Password： guest/guest

• Connect to workshop router– You have to connect workshop router from terminal server

– Workshop router management IP： 192.168.AS#.R#• ex. Router management IP of AS101 R2： 192.168.101.2• Please use “69” in AS69000• Please use uplink ISP AS# as 4-byte customer ISP AS#

– Only guest privilege is permitted in transit and demo AS• Transit AS： AS100, AS200, AS69000• Route-Reflector demo： AS101, AS201 and their customer AS• Confederation demo： AS102, AS202 and their customer AS

2009.11.18 18


• Provide Route-Reflector topology only• IOS test environment

– AS100• Router management IP： 192.168.100.R#





• JUNOS test environment

2009.11.18 19

4-byte ASN in a 2-byte ASN BGP domain

• Check 4-byte ASN in a pure 2-byte environment– IOS

• show ip bgp

– JUNOS• show route protocol bgp• show route protocol bgp extensive

• Add a new 4-byte ready customer router to ISP 2-byte router– Create an eBGP session between R3 and R6

– Create an eBGP session between R3 and R7

• Check BGP information in R6 and R7

2009.11.18 20

Add 4-byte ASN ready router in a BGP domain

• Add a new 4-byte ready border router– Create an iBGP session between R4 and R2

– Create an eBGP session between R4 and AS69000 R4

• Add a new 4-byte ready edge router– Create an iBGP session between R5 and R2



• Check BGP information in R4, R5, R7 and R8

2009.11.18 21

4-byte ASN BGP policy discussion

• Aggregate BGP route– In R3：

• aggregate BGP routes from R6 and R7

– In R5：• aggregate BGP routes from R7 and R8

• AS path regular expression– In R4：

• set local preference by AS path• set route filter by AS path

– In R5：• set local preference by AS path• set route filter by AS path

2009.11.18 22

Q & A

2009.11.18 23

Backup slide

2009.11.18 24


AS69000AS69000AS100AS100

AS103AS103

AS68103AS68103AS67103AS67103AS66103AS66103

F1/0

FE1/0 FE1/1FE1/0 FE1/0

eBG

PeB

GP

iBG

P






enable: admin


enable: admin







172.103.6.0/24172.103.66.0/24 172.103.7.0/24

172.103.8.0/24172.103.68.0/24

<- 172.103.67.0/24 172.103.69.0/24 ->

F1/0

2.2/16 4.4/16

R2 R4F1/1F1/1

R1

R3

R2

R4

R5

R6 R7 R8

F1/0F2/0 F2/0

F1/1

F2/1

F2/0

F2/1F1/0 F1/1

F2/1F2/0F1/0

F1/1F1/1

F1/0

F2/1 F2/0F2/1

10.103/16

10.169/24

2009.11.18 25


AS69000AS69000AS100AS100

AS104AS104

AS68104AS68104AS67104AS67104AS66104AS66104

F1/0

FE1/0 FE1/1FE1/0 FE1/0

eBG

PeB

GP

iBG

P






enable: admin


enable: admin







172.104.6.0/24172.104.66.0/24 172.104.7.0/24

172.104.8.0/24172.104.68.0/24

<- 172.104.67.0/24 172.104.69.0/24 ->

F1/0

2.2/16 4.4/16

R2 R4F1/1F1/1

R1

R3

R2

R4

R5

R6 R7 R8

F1/0F2/0 F2/0

F1/1

F2/1

F2/0

F2/1F1/0 F1/1

F2/1F2/0F1/0

F1/1F1/1

F1/0

F2/1 F2/0F2/1

10.104/16

10.169/24

4 byte as number workshop material

Technology

byte representation

byte member asn

byte asn bgp domain

byte asn recap asdot

byte asn recap limitations

byte asn recap changes

byte asn ready router

byte available login