Internet Backbone Routing

1
Internet Backbone Routing

• Masaki Hirabaru
• ltmasaki_at_k-isit.or.jpgt
• ISIT, Japan / Merit Network, US

2
Contents

• Global Routing over the Internet Backbone
• 1) Internet Routing Exchanges (IXes)
• 2) Internet Routing Registries (IRRs)
• 3) Internet Routing Analysis (incl. IPv6)

3
Network Access Point (NAP)
ISP
ISP
RA
ISP A
NAP
NAP
B
RA
C
ISP
NAP
ISP Z
NAP
RA
RA
ISP
ISP
4
Merit Route Server Package

• Scalable, reliable routing system for exchange
  point
• Performance improvement by separating routing and
  packet forwarding
• Easy router configuration
• Decrease CPU memory requirements
• Redundant servers
• Gathering routing statistics

ISP
ISP
ISP
ISP
Layer 2 Inter-connect
Route Server
Route Server
Automatic configuration
Internet Routing Registry (IRR)
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Major Public Internet Exchanges (US)
Sprint NAP (New York)
AADS NAP (Chicago) Incl. STARTAP NGIX-Mid
MAE-West (San Jose)
NGIX-East
MAE-Central (Dallas)
Merit
MAE-East (Washington DC)
NGIX-West
PacBell NAP (San Francisco? Los Angeles)
PAIX (Palo Alto)
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Gathering Routing Info
MRT, Zebra
ISP
ISP
BGP
RA
ISP A
NAP
NAP
B
RA
C
ISP
NAP
ISP Z
NAP
RA
RA
ISP
ISP
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Snapshots (Looking glass) vs. Raw BGP data
telnet, SNMP, or similar

• Couldnt catch rapid changes
• Huge full routing table

DB
R
BGP (multi-hop) connection

• R2 must be able to dump routing info
• R1 (may) needs to modify its configuration

DB
R1
R2
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Internet Routing Analysis

• Internet Performance Measurement and Analysis
  Project (IPMA) http//www.merit.edu/ipma

9
Global BGP Routing Table Collected by Geoff
Huston with Erik-Jan Bos
MAE-East
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BGP (Border Gateway Protocol)
A
192.168.2.0/24
AS1
AS2
B
192.168.1.0/24
R
R
C
192.168.3.0/24
R
AS3
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(No Transcript)
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Examples of Analysis

• Reserved or unregistered networks
• Reserved or unallocated AS numbers
• Host or un-aggregated networks
• IRR consistency (ex. origin AS)
• Instability
• Availability

routing-problems_at_merit.edu 6bone-routing-report_at_me
rit.edu To subscribe them, send a request to
majordomo_at_merit.edu.
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6bone Routing Report
This report is for 08/18/00, peering with
VIAGENIE (AS10566) CISCO (AS109) UUNET-US
(AS12199) (AS13676) (AS13901) SICS (AS2839)
MIT-SIPB (AS3) ETRI (AS3748) CERNET (AS4538)
6COM (AS561) CAIRN (AS7081) NUS-IRDU (AS7610)
NC-REN (AS81) ------------------------------------
--------- Size of 6Bone Routing Table Max
158, Min 151, Average 153 61 pTLAs (in
3ffe/16), 23 sTLAs (in 2001/16) 120
Unique Autonomous System (AS) numbers BGP4
Traffic Summary Announcements 16401
Withdraws 5827 Unique Routes 177
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Unknown AS Numbers (not in 6bone
registry) Format AS-Path (Unknown-AS-Number --
Availability) --------------------------------
10566 5408 1752 8627 5539 8319 1275 3748 109 6346
8664 44700 (8627 6346 44700 -- 100) 109 33
2914 6175 10318 1849 1752 8627 8954 3333 1103
3274 2839 237 3748 1275 293 3425 11537 (8627 8954
3333 -- 15) 109 6346 12346 (6346 -- 98) 109
6346 3113 12346 4664 3005 9009 8664 (6346 3113 --
0) .. Unknown Prefixes (not in 6bone
registry) Format Prefix path AS-Path (Origin-AS
-- Availability) --------------------------------
2000/3 path 109 6346 3113 12346 4664 3005
9009 8664 (ICM-PL -- 0) 194.182.135.0/120
path 561 5408 1752 8627 5539 4554 3748 3462 3263
(TELEBIT -- 100)
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Poorly Aggregated Announcements (gt24 in
3ffe0000/17 or gt28 in 3ffe8000/17 or gt35 in
2001/16) Format Prefix path AS-Path
(Origin-AS -- Availability) asterisk() means
the route is within its pTLA ---------------------
----------- ICM-PL (AS8664) announced 31
route(s) 3ffe30016/48 path 109 6346 8664
8954 ( -- 97) 3ffe240e/48 path 109 6346
8664 2020 7345 12383 (SPRAY -- 56)
. Prefixes from Different Origin AS Format
Prefix path AS-Path (Origin-AS --
Availability) --------------------------------
(2001618/35) path 3748 4697 1752 (BT-LABS --
99) (2001618/35) path 2839 1103 8933 3172
(USOT-ECS -- 22) BAY (3ffe1300/24) path
12199 10318 (FIBERTEL -- 99) BAY
(3ffe1300/24) path 561 6175 (SPRINT -- 100)
16
The Top Five Most Active Prefixes (more than
1000 changes) Format AS-Path (Announce/Withdraw
-- Availability) ---------------------------------
- 1. ROOT66 (3ffe/24) had 10485 BGP updates
(196 unique aspaths) 3748 4554 (592/88 -- 60)
10566 3748 4554 (591/99 -- 60) 2839 5609 4554
(203/15 -- 52) .
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8-1-2000
Every 15 minutes at MAE-East
18
8-1-2000
Every 15 minutes at 6bone.merit.edu
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Withdraw Convergence
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http//www.merit.edu
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List of Useful Tools

• IPv6 Reports and Statistics by CSELT
  http//carmen.cselt.it/ipv6/stats.html
• Public Looking Glass (a list available at
  http//www.merit.edu/ipma/tools/lookingglass.html
  )

22
List of Related Major Projects

• IPMA (http//www.merit.edu/ipma) by UM and Merit
  CAIDA (http//www.caida.org)
• Routing Information Service Project by RIPE NCC
  (http//www.ripe.net/ripencc/pub-services/np/ris-i
  ndex.html)
• International Internet Performance Measurement
  Project by APAN