Ethernet Frame Calculations

This is to show you on how to calculate the maximum frames per second that you can achieve in a certain frame size and maximum throughput you can achieve in an FS:

Maximum FrameRate = BW(bits per seconds) / Total FrameSize (FrameSize+Preamble+IFG)*8(bits)

Note: IFG or Inter-Frame Gap is 9.6us = to 12 bytes and preamble which is equivalent to 8 bytes

Example1: To know the maximum frame rate of 64byte framesize for a 1G ethernet

Max FrameRate = 1,000,000,000 / (64 + 8 + 12)*8
= 1,000,000,000 / 84bytes * 8
= 1,000,000,000 / 672
= 1,488,095 frames per second

Througput = FrameRate * FrameSize * 8 (to convert in bits)

Example2: To know the link layer throughput of a 64bytes frame size

Throughput = 1,488,095 * 64 * 8
= 1,488,095 * 512
= 761,904,760 or 761.9mbps

How-to connect your emulated router in dynamips to an Ixia Chassis

- Download and install Dynamips for windows installer from this link http://sourceforge.net/project/showfiles.php?group_id=160317&package_id=192619&release_id=593633

- Double click on the "Network Device List" icon found on your Desktop, this will list all the network adapters installed in your PC. Copy the loopback adapter’s code (NOTE: code and name of the loopback adapter may be different on every PC).

- Go to this directory “C:\Program Files\Dynamips\sample_labs\simple1” and edit the file simple1.net in notepad. Paste the code and add a few lines in the notepad as shown below:

# Simple lab

ghostios = true #this is required to properly allocate resources on your PC
sparsemem = true
model = 7200

[localhost]

[[7200]]
#NOTE: copy and paste the filename of the image as shown below
image = \Program Files\Dynamips\images\c7200-k91p-mz.122-25.S9.bin
# On Linux / Unix use forward slashes:
# image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
npe = npe-400
ram = 160

[[ROUTER R1]]
s1/0 = R2 s1/0
F0/0 = NIO_gen_eth:\Device\NPF_{7540571C-5165-42D2-8C24-7EE272F46961}

- Double click on the "dynamips server" icon found in your desktop and double click on the "simple1.net" file found in the sample_labs directory as stated in the previous step.

- You can then now configure your emulated routers by typing “telnet R1” and a new window will appear for the telnet session.

- Configure the IP address of your F0/0 interface in your R1 router on the same subnet as your loopback adapter’s IP address so they can ping each other and configure a routing protocol as well.
Example:
Router(config)# interface F0/0
Router(config-if)# ip address 192.168.1.1 255.255.255.0
Router(config-if)# no shut
Router(config)# router bgp 65500
Router(config-router)# neighbor 192.168.1.254 remote-as 65501

- Connect one of the Ixia's test port to your laptop or desktop and create a BGP test script in IxNetwork. Use the parameters based on your BGP configuration in your emulated router.

- Once both are configured, run the protocol in the IxNetwork and notice monitor the logs in your emulated router. BGP has been established.