The MPLS WG Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] doubt regarding transport address advertisement (LDP/RFC-3036)
Ashish, > <html><DIV> > <P>The following sections are picked up from RFC 3036.</P> > <P>------------section 1-------------------</P> > <P><FONT color=#3300cc>"An LSR MUST advertise the same transport address in all Hellos that advertise the same label space. This requirement ensures that two LSRs linked by multiple Hello adjacencies using the same label spaces play the same connection establishment role for each adjacency."</FONT></P> > <P><FONT face="Courier New" size=2> ----------section 2--------------------------</FONT></P> > <P><FONT face="Courier New" size=2><FONT color=#330099>LSR1 determines the transport addresses to be used at its end (A1) and LSR2's end (A2) of the LDP TCP connection. Address A1 is determined as follows:</FONT></P> > <P><FONT color=#330099>a. If LSR1 uses the Transport Address optional object (TLV) in Hello's it sends to LSR2 to advertise an address, A1 is the address LSR1 advertises via the optional object;</FONT></P> > <P><FONT color=#330099>b. If LSR1 does not use the Transport Address optional object, A1 is the source address used in Hellos it sends to LSR2.</FONT></P> > <P>---------------------end-of-section2-------</P> > <P>Suppose there are multiple links between LSR1 and LSR2. IF LSR1 does not use the Transport Address optional object, the Transport address will be the source address used in HELLOs it sends to LSR2 (as specified in section-2) and HELLOs sent on multiple links will be having different source addresses.</P> > <P>BUT RFC-3036 clearly says: "An LSR MUST advertise the same transport address in all Hellos that advertise the same label space". (Refer section-1 given above). How can it be done?</P> In this case, LSR1 is violating the protocol. Suppose links 1, 2, and 3 connect LSR1 and LSR2, and suppose LSR1 wants to advertise the same label space in the Hellos it sends on these links. If LSR1 omits the Transport Address TLV for Hellos on link 1, then it must use the Transport Address TLV for Hellos on links 2 and 3 to specify the source address used in its link 1 Hellos. Bob > <P>I hope my interpretation of given sctions are correct.</P> > <P>Regards</P> > <P>-Ashish</P> > <P></FONT><BR></P></DIV> > <DIV></DIV> > <DIV></DIV> > <DIV> </DIV><br clear=all><hr>Get your FREE download of MSN Explorer at <a href="http://explorer.msn.com">http://explorer.msn.com</a><br></p></html>
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