ltdraftietfmplslsppingrelayreply07gt L Jin J Luo T Nadeau G Swallow Changes in draft07 LSP Ping Relayed Echo Reply Stack Object Added Source Address of Replying Router Destination Address Pointer ID: 142124
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Slide1
LSP Ping Relay Reply<draft-ietf-mpls-lsp-ping-relay-reply-07>
L. Jin
J.
Luo
T. Nadeau
G. SwallowSlide2
Changes in draft-07
LSP Ping Relayed Echo Reply Stack Object: Added
Source Address of Replying Router
Destination Address Pointer
LSP Ping Relayed Echo Reply Stack Entry
Eliminated Address Length since it is implied by the type
Relay Node Address Stack description
Moved procedural information into Section 4, Procedures
Generalized MTU exceeded error
Generally useful, wider
applicabilitySlide3
Changes in draft-07 (2)Procedures
Updated text (both technical changes and clarifications)
Changed many SHOULDs to MUSTs
Section 4.7, Impact to
Traceroute
Updated to use Source Address of Replying Router
Section
5, LSP Ping Relayed Echo Reply Example
Updated example to use changed proceduresSlide4
Relayed Echo Reply Stack Object
Source
Address of Replying
Router
Had been carried in Address stack
Confused semantics, often did not even belong there
Used for loop-detection and
displayDestination Address Pointer
0
1 2 3
0
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
Length
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Initiator Source Port |
Reply
Add
Type
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Source Address of
Replying
Router (0, 4, or 16
octects
)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Destination Address Pointer
|
Number
of
Relayed
Addresses
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~
Stack
of
Relayed
Addresses
~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+Slide5
Source Address of Replying Router
Semantic Issue
Procedures mandated adding the IF address of replying router at the bottom of the stack
Adding other address optional
In
example below ASBR 2 MUST add 10.0.0.2 at BOS, but that address is not reachable from ASBR 4!
Address needed for relaying must be reachable through the interface from which the LSP ping would have been forwarded if TTL had not expired
AS Red
AS Blue
PE2
ABR
PE
1
ASBR 2
ASBR 4
ASBR 4
ASBR 5
169.0.0.2
169.0.0.3
169.0.0.4
169.0.0.5
10.0.0.2
10.0.0.2Slide6
Loop Detection
Procedures
said a
the
next relay node address MUST be located before the source IP address of the received Relayed Echo Reply which MUST be also in the stack
In example below
address 10.0.0.1 is used in both
ASes Added Destination Address Stack Pointer
Points to address to which the message is being
sent
AS Red
AS Blue
PE2
PE
1
ASBR 2
ASBR 4
169.0.0.2
169.0.0.3
10.0.0.2
10.0.0.1
10.0.0.1Slide7
Mandatory address in stackMandated adding an address
reachable through the interface from which the LSP ping
would have been forwarded at the BOS
If a
router is
hiding
its
addresslocated at an addressing domain boundarye.g. AS boundary or between areas
u
sing BGP-LU (RFC3107)
vs
IGP then a Null address MUST be added with the K bit setSlide8
Stack processing
Procedures in two cases ignored the significance of the K bit
When eliminating addresses, this can only be done from the last entry with the K bit set to the end
When choosing the next relay router MUST not use one above the
last entry with the K bit set Slide9
Next Steps
Workgroup
review (requested March 7)
MPLS-RT review (in progress)
Address comments
Last call