1. ANCP Best Practice–Adjacency Carrier Analysis Thomas Haag; haagt@telekom.de Birgit Witschurke, b.witschurke@telekom.de

2. July 2010IETF ANCP Working Group2 ANCP Adjacency – keepalive Timer Status quo in IETF ANCP drafts: ANCP protocol draft and ANCP MIB draft define the keepalive Timer referring to adjacency principles described in RFC3292 Protocol draft Chapter 4.3.2 ANCP Adjacency Procedures …Once the adjacency is established, periodic adjacency messages (type ACK) MUST be exchanged. The default for the ACK interval to be advertised in the adjacency messages is 10 sec for ANCP. The actual value SHOULD be configurable and is an implementation choice. MIB draft ancpAnSessionConfigAliveTimer OBJECT-TYPE SYNTAX Unsigned32(1..255) UNITS "deciseconds" MAX-ACCESS read-create STATUS current DESCRIPTION "The timer specifies the nominal time between periodic adjacency protocol messages generated by the access node. It is a constant for the duration of an ANCP session. The timer is specified in units of 100ms. The value of this object is persistent." DEFVAL { 100 } ::= { ancpAnSessionConfigEntry 7 }

3. July 2010IETF ANCP Working Group3 ANCP Adjacency – keepalive Timer Best practice Since 2006 field experience of inter working AN / NAS in DT network: First time Timer T1 was set to 10sec per default problem in performance of NAS side when operating multiple ancp session in parallel (>xyz) RFC 5851 R-5: The ANCP MUST be scalable enough to allow a given NAS to control at least 5000 Access Nodes 5000 adjacency connections per NAS (w/o partitioning) send randomly adjacency acknowledge every 10 sec. in average every 2ms one adjacency message processed -> performance issue Way out was setting Timer T1 = 25 sec. -> every 5ms one adjacency message to be processed Considering partitioning (R-37, RFC5851) the number of adjacency may increase (>5000) Recommendation: For operating ANCP in large scale network it is proposed to set a value of 25 sec per default.

4. Thank You!