Point-to-Point Serial Link

Bill Kaster

OK, I'd like to confirm a couple things. I've got the following output:

R3#show int s0
Serial0 is up, line protocol is up
Hardware is HD64570
Internet address is 192.168.2.60/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: CDPCP, IPCP, loopback not set
Last input 00:00:15, output 00:00:03, output hang never
Last clearing of "show interface" counters 01:20:59
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 0/2/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
172 packets input, 7696 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
337 packets output, 10831 bytes, 0 underruns
0 output errors, 0 collisions, 165 interface resets
0 output buffer failures, 0 output buffers swapped out
218 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
R3#show cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
R2 Ser 0 130 R 2524 Ser 0
R3#show cdp neighbors detail

---

Device ID: R2
Entry address(es):
IP address: 192.168.2.70
Platform: cisco 2524, Capabilities: Router
Interface: Serial0, Port ID (outgoing port): Serial0
Holdtime : 170 sec

Version :
Cisco Internetwork Operating System Software
IOS (tm) 2500 Software (C2500-C-L), Version 12.2(13)T, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2002 by cisco Systems, Inc.
Compiled Sat 16-Nov-02 13:00 by ccai

advertisement version: 2

1) At the very bottom it says "advertisement version: 2", and I'm wondering if this refers to RIPv2 or not?
2) Do 2500 series routers (12.2(13)) propagate RIP1/2 by themselves as the default routing protocol?
3) Both PPP and Frame Relay are WAN technologies, but I'm not entirely certain what the significant differences are between the two. PPP is used on point-to-point dedicated leased lines, while Frame Relay normally isn't, being a packet switched technology that ISPs use to service many customers who share their bandwidth?

Anyway, Frame Relay seems a bit involved conceptually, especially when you get past the CCNA level, but I just wanted to understand the basics after setting up a PPP serial link for the first time.

Paul Boz

Regarding question 1 - Version 2 simply means that it's the CDP advertisement version 2.

Regarding question 2 -

There is no default routing protocol enabled on Cisco routers. the ip routing process is enabled by default but no dynamic protocol such as rip is.

Regarding question 3 - Your understanding of PPP versus Frame Relay are accurate. PPP has support for PAP and CHAP authentication and is a preferred non-proprietary WAN technology for leased lines. You can also run PPP over Frame Relay.