4 Replies Latest reply: Nov 29, 2011 10:55 AM by Brian McGahan - 4 x CCIE, CCDE RSS

    L route on IPv6 table?

    ry

      Can someone clarify the L route on IPv6, which does not appear in IPv4. At least not on the IOS that I use.

        • 1. Re: L route on IPv6 table?
          Martin

          Local IPv6 routes concept exists only in IPv6, not IPv4.

          There are 3 types of IPv6 addresses; Global, Local, anycast; and one interface may have all 3 IPv6 addresses.

          You do not have to assign Local IPv6 address, it already assign by router using

          FE80 /10 prefix and MAC address.

           

          Keith has good videos on IPv6....

           

          link is https://learningnetwork.cisco.com/thread/36527

          • 2. Re: L route on IPv6 table?
            Brian McGahan - 4 x CCIE, CCDE

            A local route with code L is just the address that the router is listening for.  Some versions show this for both IPv4 and IPv6.

             

            R1#show ip route
            Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
                   D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
                   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
                   E1 - OSPF external type 1, E2 - OSPF external type 2
                   i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
                   ia - IS-IS inter area, * - candidate default, U - per-user static route
                   o - ODR, P - periodic downloaded static route, H - NHRP
                   + - replicated route, % - next hop override
            
            Gateway of last resort is not set
            
                  1.0.0.0/32 is subnetted, 1 subnets
            C        1.1.1.1 is directly connected, Loopback0
                  10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
            C        10.0.0.0/24 is directly connected, FastEthernet1/0
            L        10.0.0.1/32 is directly connected, FastEthernet1/0
            
            R1#show ipv6 route
            IPv6 Routing Table - default - 3 entries
            Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
                   B - BGP, R - RIP, I1 - ISIS L1, I2 - ISIS L2
                   IA - ISIS interarea, IS - ISIS summary, D - EIGRP, EX - EIGRP external
                   ND - Neighbor Discovery
                   O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
                   ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
            C   2001::/64 [0/0]
                 via FastEthernet1/0, directly connected
            L   2001::1/128 [0/0]
                 via FastEthernet1/0, receive
            L   FF00::/8 [0/0]
                 via Null0, receive
            R1#show run int f1/0
            Building configuration...
            
            Current configuration : 138 bytes
            !
            interface FastEthernet1/0
             ip address 10.0.0.1 255.255.255.0
             ip ospf network point-to-point
             duplex full
             ipv6 address 2001::1/64
            end
            

             

            The IPv4 local route is 10.0.0.1/32, while the IPv6 local route is 2001::1/128.  It just means that if the router sees a packet going to either of those addresses, the packet is for the router itself.

             

            A Link-Local (FE80::/8) address in IPv6 is a different concept than this.

            • 3. Re: L route on IPv6 table?
              ry

              Brian, I am still foggy on IPv6, so not ready to comment on the IPv6 route table, but am reasonably comfortable with IPv4. Where did the L route come from? Was it configured and under which routing protocol (if it matters).

              • 4. Re: L route on IPv6 table?
                Brian McGahan - 4 x CCIE, CCDE

                Newer versions of IOS show you the IP address assigned to the interface as a Local route in the routing table.  It doesn't change the behavior of anything, it just makes it easier to see what address the interface has assigned.  Previously you had to look at both the "show ip route" to see what the network assigned was, and then the "show ip interface brief" to see what the actual host address was.  The local route in the table shows you both at the same time.