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:- The continent in which the route is learned by AS3549
- The country in which the route is learned by AS3549
- The type of peering relationship (public exchange vs. private interconnect)
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
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