Identifying intrarealm calls with explicit addressing realm identifier attribute

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Identifying intra-realm calls with explicit
addressing realm identifier attribute
SIPPING WG Meeting IETF-57
draft-audet-sipping-add-realm-00.txt
François AUDET (audet_at_nortelnetworks.com)
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Explicit addressing realm identifier

• Allows for explicitly adding a realm-id for
  private (i.e., local) addresses
• UAs can make decisions based on the presence of
  the realm-id
• Core idea is that if both media termination in a
  session have a-priory knowledge that they have
  have IP addresses in same addressing realm, they
  can use it

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Explicit addressing realm identifier

• UA know that they have private adds in same realm
  only if they have the same realm-id
• If realm-id are different, use normal treatment
  (STUN, ICE, pray, etc.)
• If realm-id are same, use those addresses
• Need to configure realm-id only if multiple UA
  are behind same NAT
• Burden is on configuring the realm-id when needed
• Mechanism to configure outside of scope

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Relationship to ICE

• Can be used with or without ICE
• Syntax based on ICE -00
• Needs to be updated to ice-01
• Allows for better migration to ICE
• Use realm-id to handle UAs that do not support
  ICE
• Optimize for not using ICE when we know we dont
  need it

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Format of realm identifier

• Has to be globally unique
• Could be a number, VPN identifier, something that
  looks like a domain name, etc.
• New attribute
• includes an addressing-realm-type
  addressing-realm-identifier
• Example in draft looks like a domain name
• Similar to phone-context in RFC2806-bis (tel URI)
• E.g. aaddressing-realmuserdomain
  lab3.sanjose_at_foo.com