Stub Router Flag in ICMPv6 Router Advertisement Messages

Introduction A stub router is an autonomously-configuring router that provides IP connectivity between one or more stub networks and one or more infrastructure networks. A common stub 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. Stub routers are described in . This document defines a new RA flag, the "stub router" flag, which stub routers use to identify RAs sent by other stub 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.

Stub Router Flag The "Stub Router" flag is router advertisement flag bit TBD. The stub router flag is to be used by stub routers. The use of this flag is documented in . Devices that do not implement MUST NOT set the stub router flag, and MUST silently ignore the stub 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 "IPv6 ND Router Advertisement flags" registry of , as specified below:

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

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