Hi Danny, I was intentionally vague here to see what feedback arose.
So in my email, I neglected to mention that the Source Address I was talking about modifying as a result of changing the contents of the packet, is the Layer 2 Source MAC Address. For a device to modify the contents of a packet, or in this case for the higher layer entity to terminate the packet, and create a new packet, in order to preserve normal networking rules, then in theory the packet should use the address of the device that modified the packet. If we have a case where 1588 PTP over Ethernet is being transported within a pseudowire and MPLS LSP, and the only addresses modified are the Layer 2 MAC Addresses(of the Layer 2 MAC Address encapsulated within the PW and the Layer 2 MAC address of the Ethernet Transport for the MPLS stack), would this cause any problems for NAT? Regards, Anthony -----Original Message----- From: Danny Mayer [mailto:[email protected]] Sent: 05 December 2011 12:37 To: Anthony Magee Cc: Yaakov Stein; [email protected]; Shahram Davari; '[email protected]' Subject: Re: [TICTOC] FW: I-D Action: draft-ietf-tictoc-1588overmpls-02.txt On 11/29/2011 1:35 PM, Anthony Magee wrote: > Hi Yaakov, > > The layer violation issue is something which I believe needs further discussion. > > If a higher layer entity is placed inside a device and is used to act as the Transparent Clock i.e. calculating residence time and modifying the correction field in the layer with which that higher layer entity is associated, one could use an identifier such as a label, or a multicast Destination address in order to address that higher layer entity, allowing it to make the change without it being a layer violation. Then on the transmit side, there is nothing specifically incorrect in a device modifying the Source Address of the packet sent from a Transparent Clock within the scope of IEEE 1588 and this would be needed in order to indicate that the device has effectively created a new packet - however, the function of the node is still that of a Transparent Clock. > There would be all sorts of violations if you change the Source Address. NAT is bad enough without some other router also diddling with addresses. Don't do that. Danny _______________________________________________ TICTOC mailing list [email protected] https://www.ietf.org/mailman/listinfo/tictoc
