Measurable Objects - Provider router and gateway of the xDSL network (DSLGW)
Relating chapters: xDSL subnetwork, Classic ADSL DSLAM, Improved ADSL2 DSLAM
Build-up of the router and gateway
Router and gateway are nothing else, that a quick PC, to which the following interfaces are connected:
- 2 x 155 Mbit/s-os STM-1/ATM interface
One of the interfaces encapsulates the Ethernet-frames to be appropriate form for the classic ADSL DSLAM in the xDSL network (gateway function).
The other interface is not in use.
- 3 x 100BASET Ethernet interface
One of the interfaces routes the IP packets to the improved ADSL2 DSLAM in the xDSL
network.
We can access to the public Internet through the second interface.
The third interface is not in use.
There is a Debian GNU/Linux 4.0 operation system running on the PC, which has also a router software part. There is also a PPP server (access concentrator AC) (V3.8-11) running under the operation system, which makes the connection setup and the eligibility control between the users and the provider. PC operates continuously from an uninterruptible power supply.
Handling surface of the router and gateway
We can handle this program with commands through a console. Console serves several PCs, it accesses to the tools through a console switch. That is why we should switch over the console, till the prompt of the router:
dslgw:~# (/root/dslgw)
appears on the monitor.
Important note: It is not necessary to modify the parameters of the router during the measurement exercise, so don't do it!
Information necessary to do the measurement exercise can obtained from the database of the router using the following commands:
- ifconfig -a | more - listing interfaces (identifiers, MAC address, IP address)
- ps - list of running processes
- ps -ef | grep ppp - list of running processes which names contain the string "ppp"
Router and PPP configuration data can be obtained from the following files:
/etc/ppp/chap-secrets -> password file
iptables -> script file
- iptables -L -t ->NAT
- iptables -L INP -n -> firewall
route -n -> routing table
/etc/firewall -> NAT (MAC address, internal interfaces)
/etc/init.d -> firewall, iptables, pppoe.up
/root/ATMBRIDGE/setup_br2684_DSL ->assignment of IP addresses and VPI/VCI identifiers (classic STM-1/ATM DSLAM)
Some Linux commands, as a reminder:
- ~ - reference to one's own directory
- cat - printing out of the content of the file to the stdout
eg.: cat /etc/ppp/chap-secrets
- grep - searching for string/pattern in a file
- help | more - listing commands
- man - manual - printing out of manual belonging to the key words, programs,
e.g. man ps, man ifconfig, man pppoe-server
- mc - midnight commander - a program similar to Norton Commander
- | more - listing to the bottom of the page
- ^Z - escape from a command
- tcpdump (packet monitoring)
- tcpdump -i ppp0 net 10.10.1.0/24
- tcpdump -i vlan2
How to include configuration data into your report?
Preparing a list with redirection to a file is possible.
eg.: ifconfig -a > cfgfile.txt
Files can be brought out from the DSLGW to the reporting PC with WINSCP.
(IP address of the DSLGW IP, the login name and the password can be found at the leader of the measurement.)