To be honest I have never tried such a thing but I thought it made sense that if I enabled loopback the interface should come up. I now tried reenabling keepalives and the interface is still up but it shows itself to be in the looped state:
C7507MIX#sh int ser 4/1/3 Serial4/1/3 is up, line protocol is up (looped) Which makes sense as it's seeing it's own keepalive packets come back via the loop. I can't do this on a 2500 either but I can't tell you why, any Cisco hardware engineers out there?? oh well it's pretty much acedemic anyway, cableless serial interfaces are about as useful as a three legged horse. Dave Stefan Dozier wrote: > > Dave.... > > If there's no cable installed in Serial4/1/3, obviously I (atleast) > need to broaden my level of research on why you do can accomplish > that feat on 7500 series routers but not on 2500 series routers! > > It's just not happening here! > > But hey....that's not a problem, don't mind expanding my horizons and > if and when I find an answer, I 'll post some feedback here. > > Thanks for the info Dave.... > > Priscilla....my apologies! > > Off I go....to CCO! > > Stefan > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > MADMAN > Sent: Thursday, November 29, 2001 11:13 AM > To: [EMAIL PROTECTED] > Subject: Re: serial up/up w/o cable [7:27604] > > Tell you what, I got it to work just fine: > > interface Serial4/1/3 > no ip address > no ip directed-broadcast > ip route-cache distributed > loopback > no keepalive > no cdp enable > > C7507MIX#sh int ser 4/1/3 > Serial4/1/3 is up, line protocol is up > Hardware is cyBus Serial > MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255 > Encapsulation HDLC, crc 16, loopback set > Keepalive not set > Last input never, output never, output hang never > Last clearing of "show interface" counters never > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: weighted fair > Output queue: 0/1000/64/0 (size/max total/threshold/drops) > Conversations 0/0/256 (active/max active/max total) > Reserved Conversations 0/0 (allocated/max allocated) > 5 minute input rate 0 bits/sec, 0 packets/sec > 5 minute output rate 0 bits/sec, 0 packets/sec > 0 packets input, 0 bytes, 0 no buffer > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles > 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort > 0 packets output, 0 bytes, 0 underruns > 0 output errors, 0 collisions, 2 interface resets > 0 output buffer failures, 0 output buffers swapped out > 3 carrier transitions > RTS up, CTS up, DTR up, DCD up, DSR up > > Dave > > Stefan Dozier wrote: > > > > I don't think it will Priscilla! Even with the encap HDLC, > > the DCD (carrier detect) control lead must be high in order > > for the interface status to be in an "up" condition. The > > only way I know to accomplish that is with a cable inserted > > or some type of serial loopback plug, if there's such an > > animal. > > > > And obviously you can't have "line protocol" in an "up" state > > if the interface status isn't in an "up" state! > > > > Stefan > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of > > Priscilla Oppenheimer > > Sent: Wednesday, November 28, 2001 7:55 PM > > To: [EMAIL PROTECTED] > > Subject: Re: serial up/up w/o cable [7:27604] > > > > At 06:52 PM 11/28/01, Tom E wrote: > > >How can you get a serial interface to go up/up without a cable connected? > > I > > >have tried loop and no keep. > > > > What's the encap? I thought this would work if you used HDLC. > > > > Priscilla > -- > David Madland > Sr. Network Engineer > CCIE# 2016 > Qwest Communications Int. Inc. > [EMAIL PROTECTED] > 612-664-3367 > > "Emotion should reflect reason not guide it" -- David Madland Sr. Network Engineer CCIE# 2016 Qwest Communications Int. Inc. [EMAIL PROTECTED] 612-664-3367 "Emotion should reflect reason not guide it" Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=27714&t=27604 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
