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<p class="MsoNormal"><span style="color:#1F497D">Ping, anyone known it ?</span><span style="font-family:Wingdings;color:#1F497D">J</span><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Arvin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Arvin Gan <br>
<b>Sent:</b> Monday, August 13, 2018 5:42 PM<br>
<b>To:</b> bird-users@network.cz<br>
<b>Subject:</b> BGP resolvable issue<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"> <span style="background:silver;mso-highlight:silver">In </span>
<span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver">RFC4271, If the NEXT_HOP attribute of a BGP route depicts an address that is not resolvable, or if it would become unresolvable if the route was installed in
the routing table, the BGP route MUST be excluded from the Phase 2 decision function. Actually, BGP protocol is implemented this option. I notice that resolvable is checked with “rt->attrs->dest == RTD_UNICAST” , that mean the check is depend on the reachability
of route for NEXT_HOP. However, NEXT_HOP is a host address, not a subnet address, the resolvable checking in VRF is depending on ARP/NDP result for NEXT_HOP, if NEXT_HOP cannot be resolved for MAC, it should be unresolved.
<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> The description of RFC4271 for “resolvable”, I am confused whether it includes only route reachable, not includes host address reachable,
does anyone clearly understand it? <o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver">My test case:<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> BGP4----------------------------------------------------------BGP4 peer
<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> set next hop:1560::28
<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> <o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver">BGP<span style="color:#1F497D">4</span> peer route table :<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver">1560::/64 unicast [direct2 09:03:52.007] * (250)<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> dev A6IF1 --------------------------------------------------------the address of interface is 1560::15/64
<span style="color:#1F497D">,</span>generate direct route<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> unicast [bgp4 09:24:36.872 from 1560::26] (200) [?]<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="diff-html-added"><span style="font-size:10.0pt;background:silver;mso-highlight:silver"> via 1560::28 on A6IF1 -------------------------------------------------------the route is resolved in BGP4 peer based in brid,
but the address the interface of BGP4 peer is 1560::15, not 1560::28, NDP is not successful.</span></span><span class="diff-html-added"><span style="font-size:10.0pt;background:#CCFFCC"><o:p></o:p></span></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks<br>
Arvin<o:p></o:p></p>
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