The following code is from UNP

Code:
1 #include     "ping.h"

2 void
3 send_v4 (void)
4 {
5     int     len;
6     struct icmp *icmp;

7     icmp = (struct icmp *) sendbuf;
8     icmp->icmp_type = ICMP_ECHO;
9     icmp->icmp_code = 0;
10     icmp->icmp_id = pid;
11     icmp->icmp_seq = nsent++;
12     memset (icmp->icmp_data, 0xa5, datalen); /* fill with pattern */
13     Gettimeofday ((struct timeval *) icmp->icmp_data, NULL);

14     len = 8 + datalen;           /* checksum ICMP header and data */
15     icmp->icmp_cksum = 0;
16     icmp->icmp_cksum = in_cksum ((u_short *) icmp, len);

17     Sendto (sockfd, sendbuf, len, 0, pr->sasend, pr->salen);
18 }
At line 12, why 0xa5 is used to fill icmp_data? Any good reason for doing so? Can I use something else to fill icmp_data