LVA Syllabus Part 1

LVA 384.127 Syllabus Part 1

Written by: Heimo Zeilinger

Network Simulation and Configuration

The aim of the laboratory course Part 1 is to get an overview on the configuration of network components (switches, routers, network interface cards) as well as the configuration of a Layer-2 network protocol (RSTP) on a predefined network structure – see Figure 1. The course is evaluated by the completion of the tasks as well as a documentation of the work.

Fehler! Verweisquelle konnte nicht gefunden werden. shows the test network which

consists of the host systems (PC-S0, MANAGE-PC) and the network nodes (SWI1, SWI2, SWI3, SWI4, RTR1, RTR2).The MANAGE-PC represents the traffic sink and simulates the

Adapter: eth1 MAC: 00:14:6C:76:53:80 IP: 172.16.1.100. PC Hostname: PC-s0 Domain: ict.tuwien.ac.at Adapter: eth2 MAC: 00:1B:11:19:B2:17 IP: t.b.d. PC Manage-PC Domain: ict.tuwien.ac.at Adapter: MAC: 00:19:B9:AD:0C:6A IP: 172.16.1.1 Del l Pow e rC onnect 3 424 Description: managed switch Adapter: MAC: 00:19:B9:AC:FD:1F IP: 172.16.1.2 Del l Pow e rC onnect 3 424 Description: managed switch Net g ear FS 105 Description: non-managed switch Adapter: MAC: 00:18:4D:D3:97:9D IP: 172.16.1.3 Net g ear G S M 731 2 Description: managed Layer 3 switch

Adapter: MAC: 00:18:4D:D3:96:1D IP: 172.16.1.4 Net g ear G S M 731 2 Description: managed Layer 3 switch Description: management-pc (Ubuntu 7.04) Description: test-pc (Ubuntu 7.04) VCX-i Virtual Router / VRRP IP: 172.16.1.5 Adapter: MAC: 00:18:4D:D3:97:9D IP: 172.17.1.3 Adapter: MAC: 00:18:4D:D3:97:9D IP: 172.17.1.4 IP: 172.17.1.5 L1 L3 L5 L6 L7 L8 SWI1 SWI3 SWI4 RTR1 RTR2 Traffic generator Traffic sink

backbone network. The host PC-S0 represents the traffic generators. The host and node configuration is listed in the Appendix A. One Layer-2 switch (SWI1), two managed Layer-2 switches (SWI3, SWI4), and two Layer-3 switches (RTR1, RTR2) complete the network. PC-S0 and the MANAGE-PC run Linux Ubuntu 7.04. SWI1 and SWI2 are unmanaged switches.

Network configuration

 Prepare the redundant network structure proposed in Figure 1 (Subnet addresses are optional – use addresses regarding the private IP address space)

 Configure the network nodes as well as the end-systems

 Establish a connection between PC-s0 and Manage-PC (proof by ping each network node as well as end system)

 Observe the network behavior in case of shutting down the root node. Additional exercise:

 Configure the Virtual Router Redundancy Protocol (VRRP) for RTR1 and RTR2. Configure the network the way that RTR1 and RTR2 seem to be a virtual router for the Manage-PC.

 Test the failover behavior by transmitting a UDP stream through the network and shutting down the root node as well as one link of the main path. The host PC-S0 is used as traffic source which sends a continuous traffic stream to the Manage-PC – the appropriate scripts are already written and will be explained on site. Failover times and packets are analyzed by the use of the packet sniffer Wireshark.

Proposed procedure

1. Start the engines ;-)

2. Connect the network nodes to the network structure proposed in Figure 1.

3. Login to the Manage-PC, the PC-S0 as well as the managed network nodes. PC-S0 and managed network nodes are reachable from the Manage-PC (The tool Minicom is used for this task) – user and pw are provided on site.

4. Look at the IP-settings. Ensure that nodes and end-systems are in the same sub-net. 5. Configure RSTP for all manageable nodes

6. Set the appropriate routes at the end-systems 7. Test the connection between Manage-PC and PC-S0

8. Shut down the root node – the root node can be determined by a look at the configuration table. Evaluate the network behavior.

Additional tasks

1. Put the Manage-PC to a different sub-network

2. Configure VRRP on both Layer-3 switches (RTR1, RTR2) 3. Check the connection between PC-S0 and Manage-PC

4. Measure the convergence time of the network due to shutting down the root node as well as the links which form the used transmission route

In Appendix C, required Linux commands are listed. Examples for a network node configuration is listed in Appendix D.

Appendix A ­ Network components 

All nodes are listed in context to their notation in Fehler! Verweisquelle konnte nicht

gefunden werden.. For the manuals, please look at the LVA homepage -

http://www.ict.tuwien.ac.at/lva/384.127/.

Node Configuration

RTR1

Description GSM7312 L3 Managed Gigabit Switch

Model GSM7312 Serial Number 1C22725B00251 MAC-Address (burned in) 00:18:4D:D3:97:9D Software Version 6.2.0.14 Bootcode Version 3.0

RTR2

Description GSM7312 L3 Managed Gigabit Switch

Model Netgear GSM7312 Serial Number 1C22725B00227 MAC-Address (burned in) 00:18:4D:D3:96:1D Software Version 2.0.0.21

SWI4

Description Managed Layer-2 Switch

Model Dell PowerConnect 3424

Serial Number 1.3.6.1.4.1.674.10895.3006 MAC-Address (burned in) 00:19:b9:ad:0c:6a Software Version 2.0.0.21

SWI3

Description Managed Layer-2 Switch

Model Dell PowerConnect 3424

Serial Number 1.3.6.1.4.1.674.10895.3006 MAC-Address (burned in) 00:19:b9:ac:fd:1f Software Version 2.0.0.21

SWI2

Description Ethernet Switch

Model Netgear ProSafe 5 Port 10/100 Fs105 v2

SWI1

Description Ethernet Switch

Model Netgear ProSafe 5 Port 10/100 Fs105 v2

Serial Number 1D51763R03595

Host Configuration

PC-S0

Hardware

CPUs Processor 0

Vendor GenuineIntel CPU family 6

Model name Genuine Intel(R) CPU T2300 @ 1.66GHz CPU MHz 1000.000 Cache size 2048 KB Processor 1 Vendor GenuineIntel CPU family 6 Model 14

Model name Genuine Intel(R) CPU T2300 @ 1.66GHz CPU MHz 1667.000 Cache size 2048 KB FSB RAM 1 GB Network interfaces

eth0 AOPEN Inc.

Chipset Intel Corporation 82573L Gigabit Ethernet Controller IP address 128.131.81.57

MAC address 00:01:80:63:FD:CF

Hostname volare-s0.ict.tuwien.ac.at eth1 D-Link System Inc DFE-530TX rev A

Chipset VIA Technologies, Inc. VT6102 [Rhine-II] (rev 43)

IP address 172.16.1.100 MAC address 00:1B:11:19:B0:42

eth2 D-Link System Inc DFE-530TX rev C

Chipset VIA Technologies, Inc. VT6105 [Rhine-III] (rev 86)

IP address t. b. d.

MAC address 00:50:BA:FA:C8:C1

Manage-PC

Hardware

CPU Vendor AuthenticAMD

CPU family 6 Model 8 Model name AMD Athlon(TM) XP 2000+ CPU MHz 1666.666 Cache size 256 KB FSB RAM 512MB Network interfaces

eth0 ASUSTeK Computer Inc.

Chipset VIA Technologies, Inc. VT6102 [Rhine-II] (rev 74) IP address 128.131.80.228 MAC address 00:0E:A6:92:61:16 Hostname volare-pc.ict.tuwien.ac.at eth1 D-Link System Inc DFE-530TX rev C

Chipset VIA Technologies, Inc. VT6105 [Rhine-III] (rev 86)

IP address - MAC

address

00:05:5D:7B:4D:AB

eth2 D-Link System Inc DFE-530TX rev C

Chipset VIA Technologies, Inc. VT6105 [Rhine-III] (rev 86)

IP address 172.17.1.100 MAC

address

Appendix B – Protocols  

Rapid Spanning Tree Protocol

The Spanning Tree Protocol ensures a loop-free topology for a bridged Local Area Network and works on the base of OSI layer-2. STP allows including redundant links in order to provide automatic backup paths in case of link failures. Bridge loops are avoided. It is defined in the IEEE Standard 802.1D. The Rapid Spanning Tree Protocol (RSTP) – IEEE standard 802.1w – represents an evolution of STP and provides faster spanning tree convergence. For more information on RSTP please look at http://www.ict.tuwien.ac.at/lva/384.127/.

Virtual Router Redundancy Protocol

The Virtual Router Redundancy Protocol (VRRP) is a non-proprietary redundancy protocol described in RFC 3768, designed to deal with the single hop problem. Like it is explained above, in order to achieve higher network availability, the network structure shows a redundant design. However, the network gateway forms a single point of failure. Hence the VRRP is designed for combining n routers to a “virtual router” (formed out of master and backup routers) – the network gateway is formed by n routers, which seems to be one single router to the provider network as well as the end system. A short introduction to VRRP can be found on the CISCO homepage.

http://www.cisco.com/en/US/products/hw/vpndevc/ps2284/products_tech_note09186a008009 4490.shtml

Appendix C – Basic Linux Commands 

A lot of lists on basic Linux commands are placed in the www. One example is the list on

http://blog.lxpages.com/ultimate_linux.html. If you do not have any experience in Linux you

may consider working through such a page. As a start the basic commands should suffice.

Network configuration commands

The basic commands for network configuration are listed below. For specific information, please look at http://www.linuxmanpages.com/.

man XY … shows the manual page of any command XY

ping … sends echo requests to the host you specify on the command line, and lists the responses received their round trip time.

traceroute … shows the route of a packet. It attempts to list the series of hosts through which your packets travel on their way to a given destination.

ip … used to assign IP addresses to interfaces (eth0, lo, … ), setting up and displaying the TCP/IP configuration. It replaces the commands ifconfig and route in newer Linux distributions

ip route show … shows all specified routes

ip addr add <ip-addr>/24 dev eth0 … adds an ip-address to the interface eth0. /24 shows specifies the subnet prefix. /24 accords to the subnet 255.255.255.0

ip addr del <ip-addr> dev eth0 … deletes an ip-address

ip route add 192.168.1.0/24 dev eth0 … sets a route to the Locally Connected Network eth0 ip route add default via 192.168.1.254 … sets a default route

ip route delete 192.168.1.0/24 dev eth0 … deletes route from table

ifconfig … optional command to “ip” to show the network interface configuration and to configure them

Examples:

ifconfig ethXY down … deactivates the interface XY ifconfig ethXY up … activates the interface XY

ifconfig ethXY a.b.c.d netmask 255.255.255.0 … assigns the IP address a.b.c.d to the network interface ethXY and specifies the sub-netmask

route … configures the routing information for the kernel – this is needed if the sink is not placed in the same sub-net as any interface. It allows to manually set network table entries

Examples:

route add default gw 10.1.1.xy … sets the default gateway

route add -net 192.168.0.x netmask 255.255.255.0 eth0 … adds a route to the network 192.168.0.x via "eth0". route del 192.168.0.x netmask 255.255.255.0 eth0 … deletes the specified route

Appendix D – Node Configuration  

This part gives a short introduction on the configuration of a network node. As example the configuration of RSTP on the managed Layer-2 Switch Dell PowerConnect 3424 is given. Even the user interface of the managed Layer-2 and the Layer-3 switches differs, it is similar to handle. Please, look at the manuals for the commands – see

http://www.ict.tuwien.ac.at/lva/384.127/ .

On the command line of the Manage-PC type minicom ttyUSB1

Minicom is a text-based modem control and terminal emulation program for Unix-like perating systems. The serial port of the managed switch is assigned to ttyUSB1. Below, the

assignment of all network nodes is listed

After connecting to the switch, the switch’s user interface appears. Username and password will be given on site. Type

(SWI3) >enable

to reach the administration mode. With the command ? all possible commands, which can be invoked from the current mode, are listed.

With the command

SWI3# show running-config

you can have a look at the current system settings; IP settings included. SWI3# show ?

shows all possible commands and configuration settings for the command show. The same applies for all commands.

With the command

SWI3# configure

the global configuration mode is reached. With the command exit you can return to the previous configuration mode.

To change the nodes IP-address

SWI3 (config-if)# ip address 131.108.1.27 255.255.255.0 To enable spanning-tree functionality, type

SWI3 (config) # spanning-tree

With the command no spanning-tree, the spanning-tree functionality is turned off. The spanning- tree mode RSTP is chosen by

SWI3 (config) # spanning-tree mode rstp

Make sure that the different protocol timers for RSTP (hello-time, forward-time, max-age) are set to the same value on each network node. Set the timers to the minimum.

SWI3 (config)# spanning-tree forward-time 25 SWI3 (config)# spanning-tree hello-time 5 SWI3 (config)# spanning-tree max-age 10

Network Node Name

SWI3 _ttyUSB1

SWI4 _ttyUSB2

RTR1 _ttyUSB3

Set the priority for all nodes to the same value.

SWI3 (config)# spanning-tree priority 4096

After returning to the admin mode, you are able to verify spanning-tree settings with SWI3 # show spanning-tree

or

SWI3 # show spanning-tree detail

Restarting the devices is executed through the following command: SWI3# reload