I made a following connection: T60[eth0] <-> [Fa0/2]WS-C2950C-24
The connection is fine: WS-C2950C-24#show interfaces Fa0/2 status Port Name Status Vlan Duplex Speed Type Fa0/2 -> T60 connected 1 a-full a-100 10/100BaseTX WS-C2950C-24# ..and at the very moment I remove the cable either from the T60 or the switch, the "line protocol" in the switch will be down. Even if I apply following configuration to a switch port: WS-C2950C-24#sh run int Fa0/2 Building configuration... Current configuration : 163 bytes ! interface FastEthernet0/2 description -> T60 switchport mode access switchport nonegotiate no keepalive !keepalive frames are disabled no cdp enable spanning-tree bpdufilter enable end WS-C2950C-24# ..the line protocol of the switch port is down immediately if I disconnect the cable either from the laptop or the switch. So as far as I understand, keepalive frames have nothing to do with "line protocol". "line protocol" status should depend on "link integrity test" which means that port circuit continually sends signals- even during the idle periods where there isn't any traffic on the network. "link integrity test" can not be configured under software. According to O'Reilly "Ethernet" this should apply to 10BASE-T, 100BASE-TX as well as 1000BASE-T. Anyone has an other opinion? Or confirm this? :) regards, martin 2011/7/28 Scott Granados <[email protected]>: > There are more measured than simple keep alives. If you pull an interface > you lose carrier, timing, frames, and other various components of the > communication method in question. > > When you view an interface the first up indicates that the interface is > enabled and the line protocol means that in a down state you're not > receiving anything valid in terms of your communications protocol of choice. > > > -----Original Message----- From: Martin T > Sent: Wednesday, July 27, 2011 7:37 PM > To: Lukasz Bromirski > Cc: [email protected] > Subject: Re: [c-nsp] Are "line protocol" and LIT the same? > > Lukasz, > it looks like the default value for keepalive packet is 10s. However, > if I disconnect the other end from my switch port, the line protocol > will be down immediately. How to explain this? In addition, there are > interfaces, which by default don't have keepaive set(for example > WS-C3750G-24TS SFP interfaces). They have "Keepalive not set" under > "show interfaces" output. However, they still have "line protocol is > up (connected)".. How to explain this? > > > regards, > martin > > > 2011/4/26 Lukasz Bromirski <[email protected]>: >> >> On 2011-04-26 01:11, Martin T wrote: >>> >>> When Cisco switch or router port is "connected", it has status "line >>> protocol is up". As far as I know, this applies to all interface >>> types(10BASE-T, 100BASE-TX, 1000BASE-T, 1000BASE-LX10, 1000BASE-SX etc >>> with different transceivers). >>> What is this "line protocol"? I always thought "line protocol" is up >>> once any electrical pulses are detected by Rx. Or is "line protocol" >>> strictly "link integrity test"(LIT) pulses(100-200ns of electrical >>> pulses with 16ms+/-8ms interval)? Any clarification would be much >>> appreciated. >> >> "Line protocol" for Ethernet interfaces is Ethernet frame. Cisco boxes >> send Ethernet keepalive frame and when it doesn't loop back, they >> declare line protocol down: >> >> >> http://www.cisco.com/en/US/docs/ios/12_3/interface/command/reference/int_i1g.html#wp1154231 >> >> -- >> "There's no sense in being precise when | Łukasz Bromirski >> you don't know what you're talking | jid:[email protected] >> about." John von Neumann | http://lukasz.bromirski.net >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ >> > > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
