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Last Updated: January 3, 2008 Version 2.0

GBLX Customer BGP Communities

Table of Contents

Manipulation of internal Global Crossing BGP attributes
Control of route propagation
Usage of communities provided by Global Crossing.
Example Configuration

Controlling GBLX BGP Attributes

GBLX allows customers to modify various attributes of their announced prefixes within the GBLX network. Default settings for customer learned BGP prefixes are as follows:

Local Preference : 300
Metric Policy : Accept customer sent metrics
.
Customers can alter the local preference of their prefixes, thus changing whether a prefix is chosen as a best route. Many external influences can affect whether your announced prefix is chosen as best route. If you are multihomed and GBLX hears your route(s) from another provider and you alter your local preference to a value lower than the peer's value, the peer learned prefix will be chosen.

In order for you to appropriately manipulate your local preference values, the following is the standard policy applied to GBLX network peers:

Local Preference : 200
Metric Policy : Default is to set BGP MED = 50

Therefore, if a customer sets their prefix for a value of less than 200, the externally learned prefix may be chosen. Below is a list of communities that may be sent by a customer to influence the local preference value of their prefix:

Community Action
3549:100 set local preference 100
3549:200 set local preference 200
3549:275 set local preference 275
3549:300 set local preference 300
3549:350 set local preference 350

Control of Route Propagation

GBLX provides the customer limited control over how their prefixes are propagated to various network peers. This is accomplished using as-path prepending at the GBLX-Peer border. The following communities may be sent to prepend customer announced prefixes:

Community Action
3549:600 Deny inter-continental export of tagged prefix [iBGP].
3549:666 Deny inter-as export of tagged prefix (carry on AS 3549 only) [eBGP].

For a limited subset of GBLX peering connections, more granular control of announcements is provided. If GBLX sees a community matching 3549:8..., routing announcements sent to the following listed ASNs will be modified according to these rules :

 ASN  Peer  No Export   Prepend +1   Prepend +2   Prepend +3 
209 Qwest 8010 8011 8012 8013
701 MCI 8030 8031 8032 8033
1239 Sprint 8060 8061 8062 8063
1299 TeliaSonera 8250 8251 8252 8253
1668 AOL 8070 8071 8072 8073
2497 JPNIC 8080 8081 8082 8083
2516 KDDI 8100 8101 8102 8103
2914 NTT Verio 8120 8121 8122 8123
3257 Tiscali 8240 8241 8242 8243
3300 InfoNet Europe 8130 8131 8132 8133
3303 Swisscom 8140 8141 8142 8143
3320 T-Systems/DTAG 8150 8151 8152 8153
3356 Level 3 8160 8161 8162 8163
3561 Savvis 8170 8171 8172 8173
4134 ChinaNet 8230 8231 8232 8233
5511 OpenTransit 8190 8191 8192 8193
6461 AboveNet 8200 8201 8202 8203
6453 Teleglobe 8210 8211 8212 8213
7018 AT&T (US) 8220 8221 8222 8223
7738 Telemar 8290 8291 8292 8293

This example below illustrates the use of these communities.

A customer with ASN 4111 sends GBLX a route tagged with communities  "3549:8011 3549:8033 3549:8190"

When that route is reannounced across GBLX peering connections:

  • Qwest (AS 209) will see an AS path of: "3549 3549 4111"
  • MCI (AS 701) will see a path of: "3549 3549 3549 3549 4111"
  • OpenTransit (AS 5511) will not see the route at all
  • All other peers will see: "3549 4111"

Utilization of Global Crossing Internal Communities

Global Crossing currently tags all internal routes with communities which identify the following:
  1. The continent in which the route is learned by AS3549
  2. The country in which the route is learned by AS3549
  3. The type of peering relationship (public exchange vs. private interconnect)
This will allow customers to selectively prioritize classes of routes based on region, country, type, or any combination of these. Due to the granularity of the information provided, there are several different combinations of communities which customers might see.

The format of these communities is as follows:

3549:3BCCC

In this class, Continent and Country location is denoted using the following schema, with the leading 3 being a constant:

B = Continent of origin

0 = North America (and all non-continental islands from GMT through GMT-12)
1 = Europe (and all non-continental islands from GMT through GMT+12)
2 = Asia
3 = Australia (and Antarctica, should it become necessary)
4 = South America, Central America and Mexico
5 = Africa (should it become necessary)

CCC = 3 digit ISO country code which identifies the country from which the route is sourced from.

Examples:

USA = 3549:30840
UK = 3549:31826
Japan = 3549:32392

Another community of interest to customers, which provides information on the type of route, and how it may have been learned. The table below provides a list of 5 tags used to determine this, which can be filtered on accordingly.

3549:T...

T = type of route

Type Description
1 Public Exchanges
2 Private Connections
3 Reserved
4 Customers
5 Internal Routes

Example Configuration

The following example demonstrates how a customer might construct a route map to be applied to a Global Crossing peering session. (This example is not intended to be a statement of what routing policy should exist but to illustrate one way to use the information documented above.)

The route-map below modifies the routes learned from Global Crossing as follows.

  • routes learned from AS 22312 are refused (deny 5 matches access-list 10)
  • routes learned from the public exchanges assigned lpref of 100 and a metric of 600 (permit 10 matches community-list 10)
  • routes from the U.S.A. are given a local preference of 350 and a weight of 100 (permit 20 matches community-list 11)
  • routes from GBLX customers assigned lpref 350 and a weight of 10 (permit 30 matches community-list 12)
  • routes from GBLX peers are given a local preference of 200 (permit 40 matches community-list 13)
  • all other routes assigned lpref 100 (permit 50 matches community-list 13)
route-map GBLX-in deny 5 
 match as-path 10 
! 
route-map GBLX-in permit 10 
 match community 10
 set local-preference 100
 set metric 600
!
route-map GBLX-in permit 20
 match community 11
 set local-preference 350
 set weight 100
!
route-map GBLX-in permit 30
 match community 12
 set local-preference 350
 set weight 10
!
route-map GBLX-in permit 40
 match community 13
 set local-preference 200
!
route-map GBLX-in permit 50
 match as-path 1
 set local-preference 100
!
 ip as-path access-list 1 permit .*
 ip as-path access-list 10 permit _22312_
!
 ip community-list 10 permit 3549:1[0-9][0-9][0-9]
 ip community-list 11 permit 3549:30840
 ip community-list 12 permit 3549:4[0-9][0-9][0-9]
 ip community-list 13 permit 3549:2[0-9][0-9][0-9]

ISO Country Codes:

Country                                         A2      A3     Number
----------------------------------------------------------------------
ANDORRA                                         AD      AND     020
AFGHANISTAN                                     AF      AFG     004
ALBANIA                                         AL      ALB     008
ALGERIA                                         DZ      DZA     012
AMERICAN SAMOA                                  AS      ASM     016
ANTARCTICA                                      AQ      ATA     010
ANGOLA                                          AO      AGO     024
ANGUILLA                                        AI      AIA     660
ANTIGUA AND BARBUDA                             AG      ATG     028
ARMENIA                                         AM      ARM     051
ARUBA                                           AW      ABW     533
ARGENTINA                                       AR      ARG     032
AUSTRALIA                                       AU      AUS     036
AUSTRIA                                         AT      AUT     040
AZERBAIJAN                                      AZ      AZE     031
BAHAMAS                                         BS      BHS     044
BAHRAIN                                         BH      BHR     048
BANGLADESH                                      BD      BGD     050
BARBADOS                                        BB      BRB     052
BELGIUM                                         BE      BEL     056
BELIZE                                          BZ      BLZ     084
BENIN                                           BJ      BEN     204
BERMUDA                                         BM      BMU     060
BHUTAN                                          BT      BTN     064
BOLIVIA                                         BO      BOL     068
BOSNIA AND HERZEGOWINA                          BA      BIH     070
BOTSWANA                                        BW      BWA     072
BOUVET ISLAND                                   BV      BVT     074
BRAZIL                                          BR      BRA     076
BRITISH INDIAN OCEAN TERRITORY                  IO      IOT     086
BRUNEI DARUSSALAM                               BN      BRN     096
BULGARIA                                        BG      BGR     100
BURKINA FASO                                    BF      BFA     854
BURUNDI                                         BI      BDI     108
BELARUS                                         BY      BLR     112
CAMBODIA                                        KH      KHM     116
CAMEROON                                        CM      CMR     120
CANADA                                          CA      CAN     124
CAPE VERDE                                      CV      CPV     132
CAYMAN ISLANDS                                  KY      CYM     136
CENTRAL AFRICAN REPUBLIC                        CF      CAF     140
CHAD                                            TD      TCD     148
CHILE                                           CL      CHL     152
CHINA                                           CN      CHN     156
CHRISTMAS ISLAND                                CX      CXR     162
COCOS (KEELING) ISLANDS                         CC      CCK     166
COLOMBIA                                        CO      COL     170
COMOROS                                         KM      COM     174
CONGO                                           CG      COG     178
CONGO, THE DEMOCRATIC REPUBLIC OF THE           CD      COD     180
COOK ISLANDS                                    CK      COK     184
COSTA RICA                                      CR      CRI     188
COTE D'IVOIRE                                   CI      CIV     384
CROATIA (local name: Hrvatska)                  HR      HRV     191
CUBA                                            CU      CUB     192
CYPRUS                                          CY      CYP     196
CZECH REPUBLIC                                  CZ      CZE     203
DENMARK                                         DK      DNK     208
DJIBOUTI                                        DJ      DJI     262
DOMINICA                                        DM      DMA     212
DOMINICAN REPUBLIC                              DO      DOM     214
EAST TIMOR                                      TP      TMP     626
ECUADOR                                         EC      ECU     218
EGYPT                                           EG      EGY     818
EL SALVADOR                                     SV      SLV     222
EQUATORIAL GUINEA                               GQ      GNQ     226
ERITREA                                         ER      ERI     232
ESTONIA                                         EE      EST     233
ETHIOPIA                                        ET      ETH     231
FALKLAND ISLANDS (MALVINAS)                     FK      FLK     238
FAROE ISLANDS                                   FO      FRO     234
FIJI                                            FJ      FJI     242
FINLAND                                         FI      FIN     246
FRANCE                                          FR      FRA     250
FRANCE, METROPOLITAN                            FX      FXX     249
FRENCH GUIANA                                   GF      GUF     254
FRENCH POLYNESIA                                PF      PYF     258
FRENCH SOUTHERN TERRITORIES                     TF      ATF     260
GABON                                           GA      GAB     266
GEORGIA                                         GE      GEO     268
GAMBIA                                          GM      GMB     270
GERMANY                                         DE      DEU     276
GHANA                                           GH      GHA     288
GIBRALTAR                                       GI      GIB     292
GREECE                                          GR      GRC     300
GREENLAND                                       GL      GRL     304
GRENADA                                         GD      GRD     308
GUADELOUPE                                      GP      GLP     312
GUAM                                            GU      GUM     316
GUATEMALA                                       GT      GTM     320
GUINEA                                          GN      GIN     324
GUINEA-BISSAU                                   GW      GNB     624
GUYANA                                          GY      GUY     328
HAITI                                           HT      HTI     332
HEARD AND MC DONALD ISLANDS                     HM      HMD     334
HOLY SEE (VATICAN CITY STATE)                   VA      VAT     336
HONDURAS                                        HN      HND     340
HONG KONG                                       HK      HKG     344
HUNGARY                                         HU      HUN     348
ICELAND                                         IS      ISL     352
INDIA                                           IN      IND     356
INDONESIA                                       ID      IDN     360
IRAN (ISLAMIC REPUBLIC OF)                      IR      IRN     364
IRAQ                                            IQ      IRQ     368
IRELAND                                         IE      IRL     372
ISRAEL                                          IL      ISR     376
ITALY                                           IT      ITA     380
JAMAICA                                         JM      JAM     388
JAPAN                                           JP      JPN     392
JORDAN                                          JO      JOR     400
KAZAKHSTAN                                      KZ      KAZ     398
KENYA                                           KE      KEN     404
KIRIBATI                                        KI      KIR     296
KOREA, DEMOCRATIC PEOPLE'S REPUBLIC OF          KP      PRK     408
KOREA, REPUBLIC OF                              KR      KOR     410
KUWAIT                                          KW      KWT     414
KYRGYZSTAN                                      KG      KGZ     417
LAO PEOPLE'S DEMOCRATIC REPUBLIC                LA      LAO     418
LATVIA                                          LV      LVA     428
LEBANON                                         LB      LBN     422
LESOTHO                                         LS      LSO     426
LIBERIA                                         LR      LBR     430
LIBYAN ARAB JAMAHIRIYA                          LY      LBY     434
LIECHTENSTEIN                                   LI      LIE     438
LITHUANIA                                       LT      LTU     440
LUXEMBOURG                                      LU      LUX     442
MACAU                                           MO      MAC     446
MACEDONIA, THE FORMER YUGOSLAV REPUBLIC OF      MK      MKD     807
MADAGASCAR                                      MG      MDG     450
MALAWI                                          MW      MWI     454
MALAYSIA                                        MY      MYS     458
MALDIVES                                        MV      MDV     462
MALI                                            ML      MLI     466
MALTA                                           MT      MLT     470
MARSHALL ISLANDS                                MH      MHL     584
MARTINIQUE                                      MQ      MTQ     474
MAURITANIA                                      MR      MRT     478
MAURITIUS                                       MU      MUS     480
MAYOTTE                                         YT      MYT     175
MEXICO                                          MX      MEX     484
MICRONESIA, FEDERATED STATES OF                 FM      FSM     583
MOLDOVA, REPUBLIC OF                            MD      MDA     498
MONACO                                          MC      MCO     492
MONGOLIA                                        MN      MNG     496
MONTSERRAT                                      MS      MSR     500
MOROCCO                                         MA      MAR     504
MOZAMBIQUE                                      MZ      MOZ     508
MYANMAR                                         MM      MMR     104
NAMIBIA                                         NA      NAM     516
NAURU                                           NR      NRU     520
NEPAL                                           NP      NPL     524
NETHERLANDS                                     NL      NLD     528
NETHERLANDS ANTILLES                            AN      ANT     530
NEW CALEDONIA                                   NC      NCL     540
NEW ZEALAND                                     NZ      NZL     554
NICARAGUA                                       NI      NIC     558
NIGER                                           NE      NER     562
NIGERIA                                         NG      NGA     566
NIUE                                            NU      NIU     570
NORFOLK ISLAND                                  NF      NFK     574
NORTHERN MARIANA ISLANDS                        MP      MNP     580
NORWAY                                          NO      NOR     578
OMAN                                            OM      OMN     512
PALAU                                           PW      PLW     585
PAKISTAN                                        PK      PAK     586
PANAMA                                          PA      PAN     591
PAPUA NEW GUINEA                                PG      PNG     598
PARAGUAY                                        PY      PRY     600
PERU                                            PE      PER     604
PHILIPPINES                                     PH      PHL     608
PITCAIRN                                        PN      PCN     612
POLAND                                          PL      POL     616
PORTUGAL                                        PT      PRT     620
PUERTO RICO                                     PR      PRI     630
QATAR                                           QA      QAT     634
REUNION                                         RE      REU     638
ROMANIA                                         RO      ROM     642
RUSSIAN FEDERATION                              RU      RUS     643
RWANDA                                          RW      RWA     646
SAINT KITTS AND NEVIS                           KN      KNA     659
SAINT LUCIA                                     LC      LCA     662
SAINT VINCENT AND THE GRENADINES                VC      VCT     670
SAMOA                                           WS      WSM     882
SAN MARINO                                      SM      SMR     674
SAO TOME AND PRINCIPE                           ST      STP     678
SAUDI ARABIA                                    SA      SAU     682
SENEGAL                                         SN      SEN     686
SEYCHELLES                                      SC      SYC     690
SIERRA LEONE                                    SL      SLE     694
SINGAPORE                                       SG      SGP     702
SLOVAKIA (Slovak Republic)                      SK      SVK     703
SLOVENIA                                        SI      SVN     705
SOLOMON ISLANDS                                 SB      SLB     090
SOMALIA                                         SO      SOM     706
SOUTH AFRICA                                    ZA      ZAF     710
SOUTH GEORGIA AND THE SOUTH SANDWICH ISLANDS    GS      SGS     239
SPAIN                                           ES      ESP     724
SRI LANKA                                       LK      LKA     144
ST. HELENA                                      SH      SHN     654
ST. PIERRE AND MIQUELON                         PM      SPM     666
SUDAN                                           SD      SDN     736
SURINAME                                        SR      SUR     740
SVALBARD AND JAN MAYEN ISLANDS                  SJ      SJM     744
SWAZILAND                                       SZ      SWZ     748
SWEDEN                                          SE      SWE     752
SWITZERLAND                                     CH      CHE     756
SYRIAN ARAB REPUBLIC                            SY      SYR     760
TAIWAN, PROVINCE OF CHINA                       TW      TWN     158
TAJIKISTAN                                      TJ      TJK     762
TANZANIA, UNITED REPUBLIC OF                    TZ      TZA     834
THAILAND                                        TH      THA     764
TOGO                                            TG      TGO     768
TOKELAU                                         TK      TKL     772
TONGA                                           TO      TON     776
TRINIDAD AND TOBAGO                             TT      TTO     780
TUNISIA                                         TN      TUN     788
TURKEY                                          TR      TUR     792
TURKMENISTAN                                    TM      TKM     795
TURKS AND CAICOS ISLANDS                        TC      TCA     796
TUVALU                                          TV      TUV     798
UGANDA                                          UG      UGA     800
UKRAINE                                         UA      UKR     804
UNITED ARAB EMIRATES                            AE      ARE     784
UNITED KINGDOM                                  GB      GBR     826
UNITED STATES                                   US      USA     840
UNITED STATES MINOR OUTLYING ISLANDS            UM      UMI     581
URUGUAY                                         UY      URY     858
UZBEKISTAN                                      UZ      UZB     860
VANUATU                                         VU      VUT     548
VENEZUELA                                       VE      VEN     862
VIET NAM                                        VN      VNM     704
VIRGIN ISLANDS (BRITISH)                        VG      VGB     092
VIRGIN ISLANDS (U.S.)                           VI      VIR     850
WALLIS AND FUTUNA ISLANDS                       WF      WLF     876
WESTERN SAHARA                                  EH      ESH     732
YEMEN                                           YE      YEM     887
YUGOSLAVIA                                      YU      YUG     891
ZAMBIA                                          ZM      ZMB     894
ZIMBABWE                                        ZW      ZWE     716

Copyright 2008 Global Crossing, All rights reserved.

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