7 Replies Latest reply: Jul 6, 2009 4:13 AM by mduchemin RSS

    EIGRP Default Delay on outgoing Interfaces

    atacadp

      Does anyone have a good cheat sheet of what the default EIGRP delay is on all Cisco Interfaces where delay is not administratively defined?

        • 1. Re: EIGRP Default Delay on outgoing Interfaces
          Krzysztof Przybylski

          Hi,

           

           

          interface
          bandwidth (kb/s) for LAN
          Delay(us)
          Ethernet100001000
          Token ring16000630
          Fddi100000100
          Serial154420000

          Low-speed serial:

          WIC on 1600/2600/3600 series,

          sync/async interfaces on 252x,
          sync/async serial modules on 2600/3600, etc..

          11520000
          ISDN BRI & PRI6420000
          Dialer5620000
          Channelized T1 or E1n * 6420000
          Asynctty line speed100000
          Lo80000005000

           

           

           

          hope it helps

           

           

          Regards

          Pozdrawiam

           

           

          Krzysztof

          • 2. Re: EIGRP Default Delay on outgoing Interfaces
            atacadp

            Thanks for your reply, I was also looking for GRE interfaces, GE and 10GE interfaces.

            This table below is this posted on a Cisco website somewhere?  I've seen this table on another post as well.

             

            Thanks!

            • 3. Re: EIGRP Default Delay on outgoing Interfaces
              Scott Morris - CCDE/4xCCIE/2xJNCIE

              With GRE, the values are inherited from the underlying interface.

               

              http://www.cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a008012dac4.shtml#tu

               

              An ethernet interface has a delay of 1000 microseconds.

              A fast ethernet interface has a delay of 100 microseconds.

              A gigabit ethernet interface has a delay of 10 microseconds.

               

              While I don't have a 10G handy, I would assume that a 1 microsecond delay would be seen!  

               

              HTH,

               

              Scott

              • 4. Re: EIGRP Default Delay on outgoing Interfaces
                Krzysztof Przybylski

                here is another link about EIGRP GRE Delay:

                 

                IP GRE Tunnel Delay

                 

                The default delay value for a GRE tunnel interface is 500000 usec, to make one tunnel the backup interface the delay value was increase to 600000 usec. All traffic traverses the primary tunnel unless the head end device is unavailable. In the Cisco Enterprise Solutions Engineering lab test, there is only one physical interface and the tunnels are sourced off the physical interface. If there were two physical interfaces per branch, it would be preferable to source off loopback interfaces so both logical tunnels remain up in the event of a branch serial interface failure.

                The show interface commands displays delay in microsecond units. The delay interface command specifies the delay metric, in 10 microsecond units. EIGRP calculates its metric from the minimum bandwidth in Kbps for all links in the path, and the cumulative delay in microseconds for all links in the path.

                well, I'm not sure why in that particular example above delay default value is equal 500000us,

                As I understand 500000us is not default delay value for GRE ?


                Outputs shows something otherwise .........

                • 5. Re: EIGRP Default Delay on outgoing Interfaces
                  atacadp

                  Yea as far as I knew for GRE I have read the default delay is 500,000usec.  I did learn on my own that delay values administravely defined throw one off unless you read what the command is doing.    Apparently the command is measured in tens of microseconds, and the output is displayed simply in microseconds.  so if one puts 600,000 delay on a GRE interface the actual delay is 6,000,000.  That's what I am seeing.

                   

                   

                  • 6. Re: EIGRP Default Delay on outgoing Interfaces
                    Krzysztof Przybylski

                    I was confused, because it was quite strange for me that I couldn't find more direct info (except this) that default delay for GRE is 500000us,

                    So, with reference to your question, I can safely say that default GRE delay is 500000us and add below record to the "default BW/DLY table":

                     

                     

                    interfaceBandwidth (kbps)
                    Delay(us)
                    GRE tunnel9500000

                     

                     

                     

                    Regards

                     

                    Krzysztof

                    • 7. Re: EIGRP Default Delay on outgoing Interfaces
                      mduchemin

                      Hi Scott,

                       

                      Very helpful as usual, thanks for that.

                       

                      However, how is EIGRP going to deal with a delay of 1us? Is the value that EIGRP uses not in tens of us?

                      So, for a gig interface the delay showing in the "show interface" would be 10us, but EIGRP would then use a value of 1?

                      And so for a 10gig interface, the delay showing in the "show interface" would be 1us, and EIGRP would then use.... 0?

                       

                       

                      On a 6500 running 12.2(33)SXH5 I saw that the delay was showing up as 100us on a Gig interface.

                      However, the interface had auto-negotiated to 100Mb/Full duplex, would that influence the delay? Or is that cisco spotted that delay issue with high bandwidth interface and modified their default values.... I couldn't find any specific info about that with google.

                       

                      Cheers,

                      Mat