TekPoints: May 2012

Wednesday, May 30, 2012

Ixia tips

1. Before create statistic view window, do not forget to create Group View to group the ports of interest.

2. May need to clear the “Ownership” of the ports to start traffic

Some c tips

Right-sift 10 (>>10) means divide by 1024.

Left-shift 10(<<10) means times 1024.

To printf “%” sign

printf(“%%\n”);

Set up VNC

vncserver -geometry 2048x1024 :60

(or vncserver -geometry 2048x1024)

vncpasswd

Password:

Verify:

xterm

xterm -sb -sl 3000 -bg blue -fg white &

xterm -sb -sl 3000 -bg lightblue &

xterm -sb -sl 3000 -bg lightgreen &

xterm -sb -sl 3000 -bg pink &

How to launch Graphical vi manager

/usr/local/bin/vim -g -bg lightblue &

giga bytes

(Wiki)

The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 10⁹ in the International System of Units (SI), therefore 1gigabyte is 1000000000bytes.

Historically, the term has also been used in some fields of computer science and information technology to denote the gibibyte, or 1073741824 (1024³ or 2³⁰) bytes.

the International Electrotechnical Commission has been promoting the use of the term gibibyte for the binary definition. This position is endorsed by other standards organizations including the IEEE, the International Committee for Weights and Measures (CIPM) and the U.S.National Institute of Standards and Technology (NIST), but the binary prefixes have seen limited acceptance. The JEDEC industry consortium continues to recommend the IEEE 100 nomenclature of using the metric prefixes kilo, mega and giga in their binary interpretation for memory manufacturing designations.

Multiples of bytes
SI decimal prefixes		Binary usage	IEC binary prefixes
Name (Symbol)	Value	Binary usage	Name (Symbol)	Value
kilobyte (kB)	10³	2¹⁰	kibibyte (KiB)	2¹⁰
megabyte (MB)	10⁶	2²⁰	mebibyte (MiB)	2²⁰
gigabyte (GB)	10⁹	2³⁰	gibibyte (GiB)	2³⁰
terabyte (TB)	10¹²	2⁴⁰	tebibyte (TiB)	2⁴⁰
petabyte (PB)	10¹⁵	2⁵⁰	pebibyte (PiB)	2⁵⁰
exabyte (EB)	10¹⁸	2⁶⁰	exbibyte (EiB)	2⁶⁰
zettabyte (ZB)	10²¹	2⁷⁰	zebibyte (ZiB)	2⁷⁰
yottabyte (YB)	10²⁴	2⁸⁰	yobibyte (YiB)	2⁸⁰
See also: Multiples of bits · Orders of magnitude of data

Thursday, May 24, 2012

Power-on self-test (POST)

http://en.wikipedia.org/wiki/Power-on_self-test

Tuesday, May 22, 2012

Deletion of the node in link list

When Key found (current node is ptr)

next: ptr->next
previous: ptr->prev
previous's next: (ptr->prev)->next
next's previous (ptr->next)->prev

Create connection

If the key is head,
1. set head to the next
2. set next's previous to null

If key is tail
1. set tail to the previous
2. set previous's next to null

If key is in the middle
1. set previous's next to next
2. set next's previous to previous

Disconnect the current node

1. set current's next to null
2. set current's previous to null

Delete current node

free(ptr);

Traversing link list

Get pointer of the list head to local ptr, and traverse while ptr is not NULL.
At least following are necessary:

#include <stdio.h>

#include <stdlib.h>

typedef struct node {

int data;

struct node *next;

struct node *prev;

} NodeType;

NodeType *listHead=0, *listTail=0;

int listShow(void) {

NodeType *ptr;

ptr = listHead;

if(ptr == 0) {
// print "empty" and return 0;
}

while (ptr) {

printf("data = %d\n", ptr->data);

ptr = ptr->next;

}

return 0;

}

cscope

Setup:

#! /bin/sh

rm cscope.files

find . -name "*.[c|h]" -print > cscope.files

/usr/bin/cscope

Usage:

cscope –d

TAB to move to lower area from upper area

Ctrl + d to exit

Monday, May 21, 2012

Link list: 3 steps of listAdd operation

1. Allocate memory for the new element

- can be done in the add routine

2. Fill the structure data/prev/next fields for the new element

3. Connect in the linklist as follows:

Check listHead == 0 --> 1st elm --> both head and tail equal to the new elm
!= 0 --> not 1st elm --> put in after tail. then this new elm become tail.

#include <stdio.h>

#include <stdlib.h> // for malloc

// minimum needed as follows:

typedef struct node {

int data;

struct node *next;

struct node *prev;

} NodeType;

NodeType *listHead=0, *listTail=0; // this is convenient

int listAdd(int newData) {

NodeType *newNode;

newNode = (NodeType *) malloc(sizeof(NodeType));

// TBD check NULL and return if so

newNode->data = newData;

newNode->next = 0;

newNode->prev = 0;

if(listHead == 0) {

listHead = newNode;

listTail = newNode;

printf("1st node added (%d)\n", listHead->data);

return 0;

}

listTail->next = newNode;

newNode->prev = listTail;

// do not forget to set new listTail

listTail = listTail->next;

return 0;

}

Function pointer

FORMAT:

int realFunc(<params>) { return 0; }

int (*funcName)(<params>);

funcName = realFunc;

EXAMPLES:

int lbkStubFunc(int port, int mode) { return 0; }

int (*drv_eth_port_set_loopback)(int port, int mode) = lbkStubFunc;

drv_eth_port_set_loopback = lbkStubFunc;

FORMAT using typedef:

Int stub(<API interface>) { return 0; }

typedef int (*FUNCPTR) (<API interface>);

FUNCPTR tmp;

tmp = (FUNCPTR) stub;

Putting 4 bytes on the location in the buf

#include <stdio.h>

#include <string.h>

// Experiment (Linux)

// Putting 4 bytes on the location in the buf

// Getting 4 bytes from the char buf to uint32

#define DATA32 0x1234abcd;

int main(void) {

char *ptr;

char buf[16];

int i;

unsigned int value;

memset((char *)buf, 0, 16);

ptr = buf;

// put

*(unsigned int *) ptr = DATA32;

printf("*ptr = 0x%x\n", *ptr);

printf("*(ptr+1) = 0x%x\n", *(ptr+1));

printf("*(ptr+2) = 0x%x\n", *(ptr+2));

printf("*(ptr+3) = 0x%x\n", *(ptr+3));

for(i=0; i<16; i++) {

printf("buf[%d]: 0x%x\n", i, buf[i]);

}

// get

value = *(unsigned int *) ptr;

printf("value = 0x%x\n", value);

return 0;

}

/*****************************

Output

#[600]a.out

*ptr = 0xffffffcd

*(ptr+1) = 0xffffffab

*(ptr+2) = 0x34

*(ptr+3) = 0x12

buf[0]: 0xffffffcd

buf[1]: 0xffffffab

buf[2]: 0x34

buf[3]: 0x12

buf[4]: 0x0

buf[5]: 0x0

buf[6]: 0x0

buf[7]: 0x0

buf[8]: 0x0

buf[9]: 0x0

buf[10]: 0x0

buf[11]: 0x0

buf[12]: 0x0

buf[13]: 0x0

buf[14]: 0x0

buf[15]: 0x0

value = 0x1234abcd

******************************/

Sunday, May 20, 2012

Networking knowledge -- The bullet points

http://computernetworks-jw.blogspot.com

Saturday, May 19, 2012

Thread Safe?

"Every function that uses files in some way. This includes printf, scanf, getchar, and putchar (unsafe). The functions sprintf and sscanf are not included (safe)." They (former) need mutex in a certain way to serialize these operations.

Thread(or task) is an entity in multi-tasking and they can share memory (global variable) with mutex mechanism. / threads are under the same application.
An application (process) can launch multiple threads.

Process is a standalone self-contained application and it "cannot" share the global variables. (They run on the different contexts - 属性 ) They can only communicate thru IPC channel.
Multiple processes can run on a CPU.

Friday, May 18, 2012

C String Lib Reference

http://www.cplusplus.com/reference/clibrary/cstring/

Vlan setting for Ixia

Check Vlan table

#sh vlan

Codes: * - Default VLAN, G - GVRP VLANs

Q: U - Untagged, T - Tagged

x - Dot1x untagged, X - Dot1x tagged

G - GVRP tagged, M - Vlan-stack

NUM Status Description Q Ports

* 1 Inactive

2 Inactive U Te 5/0,3

3 Inactive U Te 5/1-2

Change to L2 mode

#conf

(conf)#int vlan [entry id]

(conf)#int vlan 4

FORMAT: (conf-if-vl-4)#int rang te [slot] /[port] – [port]

(conf-if-vl-4)#int rang te 10/0 - 3

(conf-if-range-te-10/0-3)#no shut

(conf-if-range-te-10/0-3)#sw

03:16:50: %RPM0-P:CP %IFMGR-5-ACTIVE: Changed Vlan interface state to active: Vl 1

(conf-if-range-te-10/0-3)#exit

Add a new entry to Vlan table

(conf)#int vlan [id]

(conf)#int vlan 4

(conf-if-vl-4)#untag ten 10/0

03:17:38: %RPM0-P:CP %IFMGR-5-ACTIVE: Changed Vlan interface state to active: Vl 4

(conf-if-vl-4)#untag ten 10/3

(conf-if-vl-4)#exit

Show Vlan Table

(conf)#exit

#03:18:07: %RPM0-P:CP %SYS-5-CONFIG_I: Configured from console by console

#sh vlan

Codes: * - Default VLAN, G - GVRP VLANs

Q: U - Untagged, T - Tagged

x - Dot1x untagged, X - Dot1x tagged

G - GVRP tagged, M - Vlan-stack

NUM Status Description Q Ports

* 1 Active U Te 10/1-2

2 Inactive U Te 5/0,3

3 Inactive U Te 5/1-2

4 Active U Te 10/0,3

Increase MTU

#conf

FORMAT: (conf)#int range ten [slot]/[port] - [port] // Need space -

(conf)#int range ten 10/0 - 3

(conf-if-range-te-10/0-3)#mtu 9252

(conf-if-range-te-10/0-3)#exit

(conf)#exit

Check line rate

#sh int tengiga | grep line-rate|TenGi

#sh int tengiga 10 | grep line-rate|TenGi

TenGigabitEthernet 10/0 is up, line protocol is up

Input 9956.00 Mbits/sec, 248909 packets/sec, 99.90% of line-rate

Output 9956.00 Mbits/sec, 248899 packets/sec, 99.90% of line-rate

TenGigabitEthernet 10/1 is up, line protocol is up

Input 9956.00 Mbits/sec, 248898 packets/sec, 99.90% of line-rate

Output 9956.00 Mbits/sec, 248909 packets/sec, 99.90% of line-rate

TenGigabitEthernet 10/2 is up, line protocol is up

Input 9956.00 Mbits/sec, 248909 packets/sec, 99.90% of line-rate

Output 9956.00 Mbits/sec, 248898 packets/sec, 99.90% of line-rate

TenGigabitEthernet 10/3 is up, line protocol is up

Input 9956.00 Mbits/sec, 248898 packets/sec, 99.90% of line-rate

Output 9956.00 Mbits/sec, 248909 packets/sec, 99.90% of line-rate

Delete an entry in Vlan table

#conf

(conf)#no int vlan [id]

(conf)#end

How to change pattern in Ixia

If Fixed is selected, 4 bytes are inserted. If Repeating is selected, 4 bytes are filled in entire packet payload.

(From this Menu) http://www.flickr.com/photos/78909208@N03/7228247588/lightbox/

Before create statistic view window, do not forget to create Group View to group the ports of interest.
May need to clear the “Ownership” of the ports to start traffic

(Menu) Stream Static View

In StatView window

Column B: mouse right click

(Menu) Edit Stream è Pattern (Random/Fix/Repeating), Size (Random/Fix) – (in Frame tab) and Rate (100%) – (in Control tab)

Start/Stop traffic è need to select column

Takes time (5 minutes or so) to reach 100% (99%) line rate

Before create statistic view window, do not forget to create Group View to group the ports of interest.

May need to clear the “Ownership” of the ports to start traffic

TekPoints

Wednesday, May 30, 2012

Ixia tips

Some c tips

Set up VNC

xterm

How to launch Graphical vi manager

giga bytes

Thursday, May 24, 2012

Power-on self-test (POST)

Tuesday, May 22, 2012

Deletion of the node in link list

Traversing link list

cscope

Monday, May 21, 2012

Link list: 3 steps of listAdd operation

1. Allocate memory for the new element

2. Fill the structure data/prev/next fields for the new element

3. Connect in the linklist as follows:

Check listHead == 0 --> 1st elm --> both head and tail equal to the new elm
!= 0 --> not 1st elm --> put in after tail. then this new elm become tail.

Function pointer

Putting 4 bytes on the location in the buf

Sunday, May 20, 2012

Networking knowledge -- The bullet points

Saturday, May 19, 2012

Thread Safe?

Friday, May 18, 2012

C String Lib Reference

Vlan setting for Ixia

How to change pattern in Ixia

Blog Archive

My Blog List

Wednesday, May 30, 2012

Thursday, May 24, 2012

Tuesday, May 22, 2012

Monday, May 21, 2012

1. Allocate memory for the new element

2. Fill the structure data/prev/next fields for the new element

3. Connect in the linklist as follows:

Check listHead == 0 --> 1st elm --> both head and tail equal to the new elm != 0 --> not 1st elm --> put in after tail. then this new elm become tail.

Sunday, May 20, 2012

Saturday, May 19, 2012

Friday, May 18, 2012

Check listHead == 0 --> 1st elm --> both head and tail equal to the new elm
!= 0 --> not 1st elm --> put in after tail. then this new elm become tail.