From: Antonio Soares (amsoares@netcabo.pt)
Date: Sun Mar 11 2007 - 20:29:46 ART
Strange, it seems CEF has influence in the DE mechanism. Here's what I got:
++++++++++++++++++++++++++++++++++++++++++++++++
R1
!
interface Serial0/0
ip address 10.10.10.1 255.255.255.0
encapsulation frame-relay
frame-relay map ip 10.10.10.2 103
frame-relay map ip 10.10.10.3 103 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
++++++++++++++++++++++++++++++++++++++++++++++++
R3
!
ip cef
frame-relay de-list 1 protocol ip list 101
!
!
interface Serial1/0
ip address 10.10.10.3 255.255.255.0
encapsulation frame-relay
frame-relay de-group 1 302
frame-relay map ip 10.10.10.1 301 broadcast
frame-relay map ip 10.10.10.2 302 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
!
access-list 101 permit icmp any any
!
++++++++++++++++++++++++++++++++++++++++++++++++
R2
!
interface Serial0/0
ip address 10.10.10.2 255.255.255.0
encapsulation frame-relay
frame-relay map ip 10.10.10.1 203
frame-relay map ip 10.10.10.3 203 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
++++++++++++++++++++++++++++++++++++++++++++++++
From R1 I sent 1000 ICMP packets to R2:
R3#sh fram pvc 302
PVC Statistics for interface Serial1/0 (Frame Relay DTE)
DLCI = 302, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0
input pkts 1000 output pkts 1000 in bytes 104000
out bytes 104000 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 8
out bcast pkts 0 out bcast bytes 0
5 minute input rate 10000 bits/sec, 11 packets/sec
5 minute output rate 10000 bits/sec, 12 packets/sec
pvc create time 4d09h, last time pvc status changed 00:17:23
R3#
R2#sh fram pvc 203
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 203, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 1000 output pkts 1000 in bytes 104000
out bytes 104000 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 8 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
5 minute input rate 6000 bits/sec, 6 packets/sec
5 minute output rate 6000 bits/sec, 6 packets/sec
pvc create time 4d06h, last time pvc status changed 00:17:47
R2#
So only 8 packets got the DE bit set. Why not 0 or 1000 ?
Now disabling CEF in R3 and sending the same 1000 ICMP packets from R1 to
R2:
R3#sh fram pvc 302
PVC Statistics for interface Serial1/0 (Frame Relay DTE)
DLCI = 302, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0
input pkts 1000 output pkts 1000 in bytes 104000
out bytes 104000 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 1000
out bcast pkts 0 out bcast bytes 0
5 minute input rate 10000 bits/sec, 10 packets/sec
5 minute output rate 10000 bits/sec, 10 packets/sec
pvc create time 4d10h, last time pvc status changed 00:20:16
R3#
R2#sh fram pvc 203
PVC Statistics for interface Serial0/0 (Frame Relay DTE)
DLCI = 203, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0
input pkts 1000 output pkts 1000 in bytes 104000
out bytes 104000 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 1000 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
5 minute input rate 7000 bits/sec, 7 packets/sec
5 minute output rate 7000 bits/sec, 7 packets/sec
pvc create time 4d06h, last time pvc status changed 00:20:40
R2#
All 1000 packets got the DE bit set.
My conclusions are: you don't need to disable CEF in order to set the DE bit
in locally originated traffic. You need to disable CEF for traffic
traversing the router. But the Doc CD says:
"Frame Relay DE group functionality is supported on process-switched packets
only."
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hwan_r
/wan_f1h.htm#wp1071786
So I'm still not sure how to handle this. It doesn't work with CEF but it
works fine with Fast Switching...
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Digital Yemeni
Sent: sabado, 10 de Margo de 2007 5:47
To: Marut.s@datacraft-asia.com; bdennis@internetworkexpert.com;
iyux2000@gmail.com; ccielab@groupstudy.com
Subject: RE: CCIE Lab : ip cef
Thanks a lot for confirming!
Since the DE is mentioned in the DocCD saying "Frame Relay DE group
functionality is supported on process-switched packets only." That brings up
the question whether Cisco is really aware of its misconception that's
creating for most people! The DocCD says something but in reality it's
something different! So which way the proctor in the lab would go when
marking the exam?!
Best Regards,
Digital
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I've not slept for the past 5 years and I'm expected to be busy for the next
57 years + The 5 CCIEs preparation adds on that a bit. Therefore, please be
concise on your email. Thank you!
>From: "Marut S@MS@DCTH-BKK" <Marut.s@datacraft-asia.com>
>Reply-To: "Marut S@MS@DCTH-BKK" <Marut.s@datacraft-asia.com>
>To: "Brian Dennis" <bdennis@internetworkexpert.com>, <iyux2000@gmail.com>,
> <ccielab@groupstudy.com>
>Subject: RE: CCIE Lab : ip cef
>Date: Sat, 10 Mar 2007 12:27:39 +0700
>
>Hi group,
>
> I have tested it again. No need to disable cef.
>
>
>Rack1R5#sh ip cef serial 3/0
>Prefix Next Hop Interface
>30.0.0.0/14 141.1.145.4 FastEthernet0/0
> 141.1.54.4 Serial3/0
>31.0.0.0/14 141.1.145.4 FastEthernet0/0
> 141.1.54.4 Serial3/0
>141.1.54.0/24 attached Serial3/0
>141.1.54.4/32 141.1.54.4 Serial3/0
>150.1.4.4/32 141.1.145.4 FastEthernet0/0
> 141.1.54.4 Serial3/0
>204.12.1.0/24 141.1.145.4 FastEthernet0/0
> 141.1.54.4 Serial3/0
>!
>interface Serial3/0
>ip address 141.1.54.5 255.255.255.0
>frame-relay de-group 1 504
> frame-relay map ip 141.1.54.4 504 broadcast
> no frame-relay inverse-arp
>end
>
>access-list 11 permit any
>frame-relay de-list 1 protocol ip list 11
>
>Rack1R5#sh frame-relay pvc | b 504
>DLCI = 504, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE =
>Serial3/0
> out BECN pkts 0 in DE pkts 58 out DE pkts 62
>
>
>
>Rack1R5#sh frame-relay pvc | b 504
>DLCI = 504, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE =
>Serial3/0
>out BECN pkts 0 in DE pkts 62 out DE pkts 67
>
>
>
>Best Regards,
>Maruto
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Brian Dennis
>Sent: Saturday, 10 March, 2007 7:44 AM
>To: iyux2000@gmail.com; ccielab@groupstudy.com
>Subject: Re: CCIE Lab : ip cef
>
>Here is how you can answer your own questions:
>
>Q) is (cef) enabled by default or not, regarding to the current IOS
>version that is used in the lab exam.
>A) Refer to the CCIE R&S Lab Equipment and IOS blueprint
>(http://www.cisco.com/go/ccie). Find what IOS version is being used.
>Look
>up the "ip cef" command in the command reference for the IOS
>version/versions being used to find out what is the default state of
>the command.
>
>Q) For example, FR de marking mechnism needs to disable ip cef, isn't
>it?
>A) Configure FR DE marking for all packets. Ensure CEF is enabled.
>Ping
>across the Frame Relay network. View the number of frames that arrived
>with the DE bit set (show frame-relay pvc). Now disable CEF and try
>again.
>
>--
>
>Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP)
>bdennis@internetworkexpert.com
>
>Internetwork Expert, Inc.
>http://www.InternetworkExpert.com
>Toll Free: 877-224-8987
>Direct: 775-745-6404 (Outside the US and Canada)
>
>
>
>
>On 3/9/07 2:49 PM, "iyux2000@gmail.com" <iyux2000@gmail.com> wrote:
>
> > Hi, group
> >
> > "ip cef" command is always mysterious for me, i want to know in
>the real
> > lab, "ip cef" is enabled by default or not, regarding to the current
>IOS
> > version that is used in the lab exam.
> >
> > And also which configurations rely on this command to work properly,
>and which
> > not.
> >
> > For example, FR de marking mechnism needs to disable ip cef,
> > isn't
>it?
> >
> > I thought that what we need to do is just disabling ip cef in some
> > circumstances if "ip cef" is activated by default in the lab.
> >
> > Thank you very much for your reply.
> >
> >
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