Symptom
On an ASR9K node running eXR failed to connect via console port using 2 stop bits although this being the expected default configuration value:
- As per public System Setup and Software Installation Guide for Cisco ASR 9000 Series Routers document:
For modular chassis RP, the console settings are baud rate 9600 bps, no parity, 2 stop bits and 8 data bits
- As per device command-line output:
RP/0/RSP0/CPU0:ASR-9000#show line console location 0/rsp0/CPU0
Tty Speed Overruns Acc I/O
con0/RSP0/CPU0 9600 0/0 -/-
Line "con0_RSP0_CPU0", Location "0/RSP0/CPU0", Type "Console"
Length: 24 lines, Width: 80 columns
Baud rate (TX/RX) is 9600, "No" Parity, 2 stopbits, 8 databits
Template: console
Capabilities: Timestamp Disabled
Allowed transports are none.
Conditions
Device is Cisco Systems ASR9K and running eXR version.
External terminal device is configured to use 2 stop bits.
Workaround
Configure external terminal device to use 1 stop bit.
Further Problem Description
Host shell show that device ttyS0 which is mapped to console uses 1 stopbit. This is the value that should be used by the external terminal server.
[host:~]$ stty --help | grep cstop
[-]cstopb use two stop bits per character (one with '-')
[host:~]$ stty -F /dev/ttyS0 -a
speed 115200 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^X; eof = ^D; eol = ; eol2 = ; swtch = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V;
flush = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop echoprt echoctl echoke
