AS31034

Overview

This document describes the BGP communities exposed to customers and peers to perform traffic engineering operations and, in particular, to selectively disable announcements toward specific destinations (direct peers, route servers, transit providers, PNIs or POPs).

By simply applying a community to a prefix, the network executes an export policy that decides where to announce and where not to announce that prefix.

1. Standard Traffic Engineering Communities

Within the AS31034 network, there exist some Standard Communities that allow customers to prepend their prefixes, to modify the Local Preference associated to their prefixes or to apply RTBH and Graceful Shutdown.

2. DASPO Communities - Distributed Advertisement Suppression Policy

The DASPO communities allow you to prevent prefix announcements toward specific peers while keeping other paths active.

3. Practical Usage Examples

Case 1 - Disable an IX while keeping transit active

Block direct peers and route servers of the IX (DE-CIX) without affecting other egress paths.

31034:0:31
31034:0:6695

Case 2 - Exclude a single transit provider

The prefix is not exported toward a given transit provider (e.g. Lumen):

31034:0:3356

Case 3 - Disable announcements toward all providers and IXs connected in a POP

Useful if you want to prevent a prefix from exiting through providers present in a specific POP:

31034:0:1

Case 4 - Block announcements only toward the Route Servers of an IX (but keep direct peers)

For example, for MIX:

31034:0:61968

Case 5 - Block announcements toward a specific PNI

For example, to block the PNI with Google:

31034:0:15169

Case 6 - Exclude a single direct peer on DE-CIX (Selective)

To keep announcing on DE-CIX, but not toward a specific bilateral peer (peer ASN: AS1234):

31034:31:1234

Case 7 - Exclude two specific peers on MIX (Selective)

To remove the announcement only toward two direct peers on MIX (e.g. AS1111 and AS2222), while keeping other direct peers active and (if not disabled) also the Route Server:

31034:35:1111
31034:35:2222

Case 8 - Combination: block Route Servers and all direct peers of MIX

To block the announcement toward MIX Route Servers and all direct peers:

31034:0:61968
31034:0:35

4. Logical Diagrams

Logical diagrams: they represent the export policy decision based on the communities.

Diagram A - Export logic (high level)

Diagram B - Disable a specific IX (direct peers + route server)

Example: 31034:0:31 + 31034:0:6695 sul prefisso.

Diagram C - “Route Server off, bilaterals on” at an IX

MIX example: only 31034:0:61968 → RS off, direct peers on.

Diagram D - “ASN-based cut” (Transit or PNI)

Example: 31034:0:3356 → do not export toward that ASN; everything else remains unchanged.

Diagram E - DASPO IX PEER Selective (blocking a single direct peer at an IX)

Example: Apply 31034:31:XXXX to stop exporting a prefix towards a specific ASN with a direct peering session over DE-CIX, leaving all other peers (and IXs/PNIs/transit providers) unchanged.