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This page outlines the BGP routing policy of AS27552 TWDX IP, including BGP communities for customer use. Any questions should be directed to ip-admin@twdx.net. |
1. Global announcements from TWDX IP are recorded under the following IRR object: AS-TOWARDEX
2. TWDX IP uses the following localpref:
50: route of last resort
100: transit default
150: peer backup
200: peer default
250: customer backup
300: customer default
400: internal originated
Routes received from customer BGP sessions are set to localpref of 300 by default, subject to
modification based on received communities as outlined below.
Localpref for non-customer peers is generally set to 200 by default.
3. MEDs from peers are overwritten unless prior arrangements for cold-potato routing have been made.
3. MEDs from customers are accepted.
4. RFC1918 and reserved networks are not accepted.
5. Advertisements with reserved ASNs in the path (64512-65535, etc) are not permitted, except for
specific customer arrangements using private ASN. In such situations, TWDX will overwrite the
origin AS to _27552$ prior to exporting to peers.
6. Advertisements containing the AS of major Tier-1 networks or AS of a network which we have a
non-customer peering relationship with are not permitted. In other words, customers are not
allowed to advertise transit for AT&T, Level 3, Comcast, etc.
7. All customer BGP sessions are prefix-filtered inbound using a customer specified import policy
as pulled from a known public IRR registry.
8. IPv4 prefixes shorter than /8 are not accepted.
9. IPv4 prefixes greater than /24 are accepted only from customers, and such prefixes will be tagged
no-export and will not be advertised beyond AS27552. Customers may elect to advertise smaller
prefixes when dual-homing into TWDX IP for inbound traffic engineering/shifting purposes, however
such prefixes will not be exported beyond AS27552. Customers should also watch out for maximum
prefix limit imposed on their BGP session, prior to making such specific advertisements.
10. Advertisements tagged with "internally originated" or "customer" BGP communities as outlined below
will have all other communities stripped at ingress.
.---------------------------------------------. | 27552:5CCCT | | |||| | | |||`- T: Route Type Code | | ||| | | |``-- CCC: Location Code (Region) | | `---- CCC: Location Code (Continent) | `---------------------------------------------' CCC: LOCATION CODE .--------------------------------------------------------------. | C CC | | | ``-- Region | | `----- Continent (7 = North America, 8 = EMEA, 9 = Pacific) | | __________________________ | | 7 .. North America (CON) | | 7 01 Boston, US | | 7 02 New York, US | | 7 05 Chicago, US | | 7 06 Washington DC, US | | __________________________ | | 8 .. EMEA (EUR/CEN) | | 8 01 London, UK | `--------------------------------------------------------------' T: ROUTE TYPE CODE .---------------------. | 1 Transit | | 2 Peer | | 4 Customer | | 5 Internal | `---------------------' EXAMPLES .--------------------------------------------------------. | Transit route learned from New York, US: 27552:57021 | | Peering route learned from Boston, US: 27552:57012 | | Customer route learned from Chicago, US: 27552:57054 | | Internal route learned from Chicago, US: 27552:57055 | `--------------------------------------------------------'
27552:50 Set LOCAL_PREF to 50 (last resort route) 27552:100 Set LOCAL_PREF to 100 (default transit route) 27552:150 Set LOCAL_PREF to 150 (less preferred than peer) 27552:200 Set LOCAL_PREF to 200 (default peer route) 27552:250 Set LOCAL_PREF to 250 (backup customer route) 27552:300 Set LOCAL_PREF to 300 (default customer route) 27552:900 Enforce hot-potato routing (set MED to 0) 27552:911 Discard traffic 65535:666 Discard traffic (IETF Blackhole per RFC 7999) 27552:912 (Internal Use Only) Non-transitive discard community 0:40000 No-export to *all* (including TWDX customers) Export only to TWDX customers, no-export to peers and transits: 27552:40005 0:40000
.----------------------------------------------.
| AAAAA:4CCCR |
| | |||| |
| | |||`--R: Request Code |
| | ||| |
| | |``-- CCC: Location Code (Region) |
| | `---- CCC: Location Code (Continent) |
| | |
| `--------- AAAAA: Target Group |
| |
`----------------------------------------------'
AAAAA: TARGET GROUP
.---------------------------------------------------------.
| 0 Everyone |
| 27552 TWDX Customers |
| 64512 All targets in North America |
| 64513 All targets in EMEA |
| ${AS} Target peer or transit AS (e.g. 3356 = Level 3) |
`---------------------------------------------------------'
R: REQUEST CODE
.------------------------------------------------------------.
| 0 No Export |
| 1 Prepend x1 |
| 2 Prepend x2 |
| 3 Prepend x3 |
| 4 If supported by target: request to treat as peer route |
| 5 Force Export (ignore less specific no-export) |
| 6 If supported by target: request to no-export |
| 7 If supported by target: request no-export to transits |
| 8 If supported by target: request no-export to peers |
| 9 If supported by target: request no-export to customers |
`------------------------------------------------------------'
EXAMPLES
.---------------------------------------------------------------.
| No Export to everyone, including TWDX customers: |
| 0:40000 |
| |
| Only export to TWDX customers; no-export to everyone else: |
| 27552:40005 0:40000 |
| |
| Prepend x1 to Level3 (AS3356) at everywhere: |
| 3356:40001 |
| |
| Prepend x1 to NTT (AS2914) at Boston only: |
| 2914:47011 |
| |
| Export to everyone, but not to Telia (AS1299): |
| 0:40005 1299:40000 |
| |
| To Level3 (AS3356): export everywhere, but not in New York: |
| 3356:40005 3356:47020 |
`---------------------------------------------------------------'
---------------------------------
Large Community Attribute Format:
---------------------------------
Note: See above descriptions under 'TARGET GROUP' to view valid options for 'Target'
27552:4CCC0:Target No-export to target
27552:4CCC5:Target Force-export to target (countermand wider scoped no-export)
27552:4CCC1:Target Prepend 1x to target
27552:4CCC2:Target Prepend 2x to target
27552:4CCC3:Target Prepend 3x to target
27552:4CCC8:Target If supported by the target, request to no-export to its peers
27552:4CCC9:Target Reset MED to 0 upon export (enforce hot-potato)
27552:911:CCC Blackhole prefix at region 'CCC'
------------------
Use Case Examples:
------------------
To only advertise to TWDX IP customers, but not to our peers and transits, send these two communities:
(27552:40005:27552, 27552:40000:0)
Global no-export to everything (including TWDX customers; provides NO_EXPORT 0xFFFFFF01 function):
27552:40000:0
To Prepend 1x to Comcast (AS7922) at everywhere:
27552:40001:7922
To Prepend 2x to Lumen (AS3356) at everywhere, but NOT in Boston (701), send these two communities:
(27552:40002:3356, 27552:47015:3356)
To blackhole a prefix (IPv4 /25-/32, IPv6 /64-/128):
Blackhole only in Boston region (701): 27552:911:701
Blackhole only in New York region (702): 27552:911:702
Blackhole at *everywhere*: 27552:911:0