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NOC International R&E network routing TEIN2 Inter-Domain Routing Guideline Ideas and Comments Xing Li.

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Presentation on theme: "NOC International R&E network routing TEIN2 Inter-Domain Routing Guideline Ideas and Comments Xing Li."— Presentation transcript:

1 NOC International R&E network routing TEIN2 Inter-Domain Routing Guideline Ideas and Comments Xing Li

2 NOC Simple Case (where BGP can handle things easily) Global transit –To tier 1 or tier 2 commodity networks Care the aggregation Care the load balancing Dont care the symmetry Peering (no transit, except for the down streams) –To domestic ISPs (bi-literal or via IX) Care the business model –To academic partners Care the performance Care the symmetry

3 NOC Complicated Case (where BGP cannot handle things easily) Global transit –To tier 1 or tier 2 commodity networks Care the aggregation Care the load balancing Dont care the symmetry Academic transit –To multiple transit backbones within academic scope Care the aggregation Care the load balancing Care the performance Care the symmetry Etc. Peering (no transit, except for the down streams) –To domestic ISPs (bi-literal or via IX) Care the business model –To academic partners Care the performance Care the symmetry

4 NOC The Real World Routing

5 NOC Possible Paths policy based routing and politics based routing

6 NOC

7

8 TEIN2 Routing Policy Overview Goal –To provide a flexible and transparent routing policy to TEIN2 NRENs Methods –Enable additive community tagging to mark the prefix announcements. –Adopt AS number prepending as the preferred BGP policy for TEIN2 traffic adjustment within TEIN2 backbone. Use ingress AS number prepending for outbound traffic adjustment, including traffic from TEIN2 POP to NRENs, GÉANT and APAN. Use egress AS number prepending for inbound traffic adjustment, including traffic from NRENs, GÉANT and APAN to TEIN2 POP. –May use Local-Preference amendment as the last resort of mechanism for fine tuning on TEIN2 traffic over the backbone.

9 NOC Communities (1)

10 NOC Communities (2)

11 NOC Communities (3)

12 NOC Routing Policy between TEIN2 POP and NREN (non-transit network)

13 NOC Routing Policy between TEIN2 POP and Transit Network

14 NOC Two Steps to Implement the Policy Identification –IP prefix –AS path regular expression –Community tag Path selection –Length of the AS path (inbound and outbound) –Local-preference (outbound) –More specific (inbound)

15 NOC Identification IP prefix –Address database –Routing database AS path regular expression –Routing database –BGP routing table Community tag –IP prefix –AS path regular expression –Community tags –Router interface

16 NOC Path Selection 0. More specific win 1. If the path specifies a next hop that is inaccessible, drop the update. 2. Prefer the path with the largest weight. 3. If the weights are the same, prefer the path with the largest local preference. 4. If the local preferences are the same, prefer the path that was originated by BGP running on this router. 5. If no route was originated, prefer the route that has the shortest AS_path. 6. If all paths have the same AS_path length, prefer the path with the lowest origin type (where IGP is lower than EGP, and EGP is lower than Incomplete). 7. If the origin codes are the same, prefer the path with the lowest MED attribute. 8. If the paths have the same MED, prefer the external path over the internal path. 9. If the paths are still the same, prefer the path through the closest IGP neighbor. 10. Prefer the path with the lowest IP address, as specified by the BGP router ID.

17 NOC Comments (1) For identification, community is the preferred mechanism, AS-path and prefix filters can also be used. The community has the advantage of –Identifying by peering relationship –Grouping prefixes/AS-paths Problems –Community exploring (AS-path regular expression) –Community mis-configuration

18 NOC Comments (2) AS-prepending as preferred method for path selection. The AS-path prepend has the advantage of –Facilitating the troubleshooting on routing problem (Local-pref is totally opaque to peers) Problems –Endless prepending Combine with –Take the Local-pref as last resort for routing adjustment

19 NOC Tough Problem Control the inbound traffic –More specific? BGP TTL? BGP scope?

20 NOC Tools, Tools, Tools Traceroute Looking glass Etc.

21 NOC Database Community definition Whois Routing

22 NOC BGP Monitoring (TEIN2-NORTH)

23 NOC The Idea of Matrix is Very Good

24 NOC Possible Bypass Methods (in the Future) MPLS services (Martini) UCLP (L0/L1/L2/L3)

25 NOC Two weeks ago in KR It is not the CERNET – KR link It is not the CERNET – APAN – KR_JP link It is not the CERNET – TEIN2 link It is the CERNET – APAN – Abilene – KR links Case 1

26 NOC Case 2.1 (IPv4) C:\Documents and Settings\xing>tracert Tracing route to ocean.net.edu.cn [ ] over a maximum of 30 hops: 1 19 ms 1 ms 2 ms 180-rtr.mm.internet2.edu [ ] 2 9 ms 2 ms 2 ms abilene-rtr.maxgigapop.net [ ] 3 14 ms 6 ms 6 ms nycmng-washng.abilene.ucaid.edu [ ] 4 34 ms 26 ms 39 ms chinng-nycmng.abilene.ucaid.edu [ ] 5 28 ms 35 ms 36 ms ms 27 ms 26 ms ae br0.chi.us.rt.ascc.net [ ] ms 221 ms 597 ms ms 409 ms 314 ms ms * 507 ms ! KOREN 10 * 355 ms * ms * * ms 407 ms 410 ms cd1.cernet.net [ ] ms * 500 ms * 346 ms * ocean.net.edu.cn [ ] 15 * 357 ms 409 ms ocean.net.edu.cn [ ] Trace complete. C:\Documents and Settings\xing> traceroute ( ) ms ms ms 2 * cd0.cernet.net ( ) ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms 7 * * ( ) ms 8 * pass.bjnet.edu.cn ( ) ms * ! STARLIGHT ( ) ms ms ms 10 nycmng-chinng.abilene.ucaid.edu ( ) ms ms ms 11 washng-nycmng.abilene.ucaid.edu ( ) ms ms ms 12 * dcne-abilene-oc48.maxgigapop.net ( ) ms ms 13 * * * 14 * * * 15 * * * 16 * * * 17 * * * 18 * * * 19 * * * 20 * * * 21 * * *

27 NOC Case 2.2 (IPv6) Microsoft Windows XP [ ] (C) Microsoft Corp. C:\Documents and Settings\xing>tracert6 2001:250:C000:20::2 Tracing route to 2001:250:c000:20::2 from 2001:468:c00:7:9d28:d329:479b:b356 over a maximum of 30 hops: 1 2 ms 8 ms 8 ms 2001:468:c00:7:100::1 2 7 ms 8 ms 8 ms washng-max.abilene.ucaid.edu [2001:468:ff:184 c::1] 3 22 ms 12 ms 12 ms nycmng-washng.abilene.ucaid.edu [2001:468:ff:1518::1] 4 28 ms 32 ms 32 ms chinng-nycmng.abilene.ucaid.edu [2001:468:ff:f15::1] 5 36 ms 36 ms 36 ms iplsng-chinng.abilene.ucaid.edu [2001:468:ff:f12::2] 6 48 ms 43 ms 47 ms kscyng-iplsng.abilene.ucaid.edu [2001:468:ff:1213::2] 7 79 ms 56 ms 66 ms dnvrng-kscyng.abilene.ucaid.edu [2001:468:ff:1013::1] 8 81 ms 83 ms 81 ms snvang-dnvrng.abilene.ucaid.edu [2001:468:ff:1017::2] ms 82 ms 90 ms 3ffe:80a::c ms 257 ms 367 ms eth xr1.ams1.gblx.net [2001:7f8:1::a500:3549:1] ms 407 ms 235 ms e b2.AMS7.Alter.net [2001:7f8:1::a501:2702:1] ms 636 ms 663 ms 2001:278:0:1000::11JP telecoms ms 509 ms * 2001:250:c000:20:: ms 503 ms 524 ms 2001:250:c000:20::2 Trace complete. C:\Documents and Settings\xing> bj-bgw-r0k#trace 2001:468:c00:7:9d28:d329:479b:b356 Type escape sequence to abort. Tracing the route to 2001:468:C00:7:9D28:D329:479B:B :250:C000:20::2 0 msec 0 msec 0 msec :250:0:3::1 0 msec 0 msec 4 msec :254:1:7::1 0 msec 0 msec 4 msec ! TEIN :254:1:3::2 40 msec 40 msec 40 msec :254:1:4::2 76 msec 72 msec 72 msec :254:8001:5::2 92 msec 92 msec 92 msec :220:1000:282::2 92 msec 92 msec 92 msec! KOREN :220:1000:42E::2 92 msec 92 msec 92 msec :220:1000:400::1 96 msec 92 msec 92 msec :220:400:200::1 96 msec 96 msec 96 msec :220:1800:200::1 96 msec 96 msec 96 msec 12 apii-juniper-ge jp.apan.net (3FFE:8140:101:1A::162) 128 msec 128 msec 128 msec! APAN 13 3FFE:8140:101::4 148 msec 160 msec 148 msec 14 tpr5-ge jp.apan.net (3FFE:8140:101:1E::5) 128 msec 128 msec 128 msec 15 transpac-la-tpr5.jp.apan.net (3FFE:8140:101:1::1) 244 msec 244 msec 256 msec :504:B:20:: msec 244 msec 244 msec 17 hstnng-losang.abilene.ucaid.edu (2001:468:FF:1114::1) 280 msec 276 msec 276 msec ! ABILENE 18 atlang-hstnng.abilene.ucaid.edu (2001:468:FF:E11::1) 296 msec 316 msec 296 msec 19 washng-atlang.abilene.ucaid.edu (2001:468:FF:118::2) 468 msec 468 msec 468 msec 20 max-washng.abilene.ucaid.edu (2001:468:FF:184C::2) 468 msec 468 msec 468 msec 21 * * * 22 * * *

28 NOC Case 3

29 NOC Case 4

30 NOC Case 5

31 NOC Remarks Assumptions –Transit and access networks are different –BGP peering is a dynamic environment Basic solution –Prefer community as the identification scheme –Prefer AS-path prepend as the path selection scheme Last resort and/or fine tone –AS-path expression as the identification scheme –Local-pref as the the path selection scheme Analysis –Matrix analysis is helpful Tools and collaborations –Traceroute, looking-glass, netflow –POC Ad-hoc solution –UCLP

32 NOC Suggestion Is it possible to create a Research and Education Network Operators Group? –Mailing-list –Meeting


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