1 - 2 - 3 - 4 - 6 - 8 - A - B - C - D - E - F - G - H - I - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Z
L2TPv3
Click on the red underlined text to get to the source
...
When the designation between L2TPv2 and L2TPv3 is necessary, L2TP as
defined in RFC 2661prop ...
... version 1".) At times,
L2TP as defined in this document will be referred to as "L2TPv3".
Otherwise, the acronym "L2TP ...
...
Details of these changes and a recommendation for transitioning to
L2TPv3 are discussed in Section 4.7.
...
... network that uses packet switching technology for data delivery.
For L2TPv3, this layer is principally IP. Other examples include
...
... packet loss occurs.
The L2TPv3 control message format defined in this document borrows
largely from L2TPv2 ...
... methods is outside the scope of this document.
Figure 3.0: L2TPv3 Structure
+-------------------+ +-----------------------+
...
... frame (e.g., sequence numbers or flags). The Default L2-Specific
Sublayer for L2TPv3 is defined in Section 4.6.
The Data Message ...
... 4.1.1) and L2TP over UDP (see Section 4.1.2). L2TPv3 implementations
MUST support L2TP over IP ...
... on incoming messages.
The Ver field MUST be set to 3, indicating an L2TPv3 message.
Note that the initial bits ...
... L2TPv2
[RFC2661], and are deprecated and marked as reserved in L2TPv3.
Thus, for UDP mode on a system that supports both versions ...
... RFC3193] defines the recommended method for securing L2TPv2. L2TPv3
possesses identical characteristics to IPsec as L2TPv2 ...
... Filtering details when protecting L2TP") may be
ignored. Instead, the selectors used to identify L2TPv3 traffic are
simply the source and destination IP addresses ...
... simply the source and destination IP addresses for the tunnel
endpoints together with the L2TPv3 IP protocol type, 115.
...
... L2TPv2, the entire message
is used in the hash in L2TPv3. In addition, instead of including the
hash digest in just the SCCRP ...
... L2TPv3 environments should be able to coexist while a
migration to L2TPv3 is made. Migration issues are discussed for each
media type ...
... media type in this section. Most issues apply only to
implementations that require both L2TPv2 and L2TPv3 operation.
However, even L2TPv3 ...
... L2TPv3 operation.
However, even L2TPv3-only implementations must at least be mindful of
these issues in order to interoperate with implementations that
support both versions ...
... If one wishes to tunnel PPP over L2TPv3, and fallback to L2TPv2 only
if it is not available, then L2TPv3 ...
... L2TPv3, and fallback to L2TPv2 only
if it is not available, then L2TPv3 over UDP with automatic fallback
(see Section 4.7.3) MUST be used. There is no deterministic method ...
... (see Section 4.7.3) MUST be used. There is no deterministic method
for automatic fallback from L2TPv3 over IP to either L2TPv2 or L2TPv3 ...
... L2TPv2. The
Ver field is used to distinguish L2TPv2 packets from L2TPv3 packets.
If an implementation is capable of operating in L2TPv2 or L2TPv3 ...
... L2TPv3 packets.
If an implementation is capable of operating in L2TPv2 or L2TPv3
modes, it is possible to automatically detect whether a peer can
support L2TPv2 ...
... modes, it is possible to automatically detect whether a peer can
support L2TPv2 or L2TPv3 and operate accordingly. The details of
this fallback capability is defined in the following section.
...
... When running over UDP, an implementation may detect whether a peer is
L2TPv3-capable by sending a special SCCRQ that is properly formatted
for both L2TPv2 ...
... SCCRQ that is properly formatted
for both L2TPv2 and L2TPv3. This is accomplished by sending an SCCRQ
with its Ver field set to 2 (for L2TPv2 ...
... with its Ver field set to 2 (for L2TPv2), and ensuring that any
L2TPv3-specific AVPs (i.e., AVPs present within this document and not
...
... AVPs are present as they would be for
L2TPv2. This is done so that L2TPv3 AVPs will be ignored by an
L2TPv2 ...
... L2TPv2-only implementation. Note that, in both L2TPv2 and L2TPv3,
the value contained in the space of the control message header ...
... L2TPv3.
If the peer implementation is L2TPv3-capable, a control message with
the Ver field set to 3 and an L2TPv3 ...
... L2TPv3-capable, a control message with
the Ver field set to 3 and an L2TPv3 header and message format will
...
... be sent in response to the SCCRQ. Operation may then continue as
L2TPv3. If a message is received with the Ver field set to 2, it
must be assumed that the peer implementation is L2TPv2-only, thus
...
...
Note Well: The L2TPv2/v3 auto-detection mode requires that all L2TPv3
implementations over UDP be liberal in accepting an SCCRQ ...
... AVP is recognized (as all AVPs defined in this document MUST be for a
compliant L2TPv3 specification), then by definition, the M bit is of
no consequence.
...
... L2TPv2 Fallback" in Section 4.7.3 requires the setting of
the M bit on all new L2TPv3 AVPs to zero if fallback to L2TPv2 is
...
... AVP" and is applicable only to a control connection. In
L2TPv3, the AVP serves the same purpose of tie breaking, but is
applicable to a control connection ...
... L2TP
control messages. The mechanism provided by L2TPv3 is described in
Section 4.3 and in the definition of the Message Digest and Control
Message ...
... endpoint authentication ensures
that an L2TPv3 control connection is only established between two
endpoints ...
... Session
ID in the L2TPv3 data header. When present, the L2TPv3 Cookie
(described in Section 4.1), provides an additional check to ensure
...
... 64-bit Cookie in
the L2TPv3 header to the admission of packets that match a given
source and destination IP address ...
... of a fast check on cleartext header information on all arriving
packets. However, since L2TPv3 uses its own value, it removes the
requirement ...
... the permitted IP addresses from hackers who may obtain and spoof
them. Further, it is far easier to change a compromised L2TPv3
Cookie than a compromised IP address ...
... 13 - Session not established due to losing
tie breaker (L2TPv3).
14 - Session not established due to unsupported
...
... Session not established due to unsupported
PW type (L2TPv3).
15 - Session not established, sequencing required
...
... Session not established, sequencing required
without valid L2-Specific Sublayer (L2TPv3).
16 - Finite state machine error or timeout.
...
... assigned within this document to maintain.
L2TPv3 Pseudowire Types
-----------------------
...
... very helpful review and comment.
Some constructs of L2TPv3 were based in part on UTI (Universal
Transport Interface ...