SNAC Router Flag in ICMPv6 Router Advertisement Messages

Introduction A Stub Network Auto Configuration for IPv6 (SNAC) router is an autonomously-configuring router that provides IP connectivity between one or more stub networks and one or more infrastructure networks. A common SNAC router example is a device that attaches a 6LoWPAN-based network to a home network, automatically providing IPv6 forwarding between the two networks without explicit operator configuration. SNAC routers are described in . This document defines a new RA flag, the "SNAC router" flag, which SNAC routers use to identify RAs sent by other SNAC routers.

Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

SNAC Router Flag The "SNAC Router" flag is router advertisement flag bit TBD. The SNAC router flag is to be used by SNAC routers. The use of this flag is documented in . Devices that do not implement MUST NOT set the SNAC router flag, and MUST silently ignore the SNAC router flag. This means that the presence or absence of the flag should not change the behavior of such devices in any way (other than that it is of course permissible to log and cache the value of the flag as part of normal router advertisement processing, where applicable.

IANA Considerations IANA is requested to allocate a flag from the "Internet Control Message Protocol version 6 (ICMPv6) Parameters", "IPv6 ND Router Advertisement flags" registry as specified below:

RA Option Bit	Description	Reference
TBD	S - SNAC Router Flag	This Document

Security Considerations This protocol shares the security issues of NDP that are documented in the "Security Considerations" section of .