Backwards Compatibility
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The current memo also addresses backwards compatibility with existing
ICMP implementations that either do not implement the extensions
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... defined herein or implement them without adding the required length
attributes. In particular, this document addresses backwards
compatibility with certain, widely deployed, MPLS-aware ICMPv4
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... ICMPv6.
In order to achieve backwards compatibility, when the ICMP Extension
Structure is appended to an ICMP message and that ICMP message ...
... Backwards Compatibility ...
... document.
In order to demonstrate backwards compatibility, Table 1 describes
how members of each application category would parse each category of
ICMP message ...
... implementation. See Section 5.5 for packet details and a discussion
of backwards compatibility.
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