What is the difference between ipt_dscp.ko and ipt_DSCP.ko in /lib/modules?

Issue

• There are files that have the same name in /lib/modules.
• One is lowercase while another is uppercase.
• For example, in RHEL5, ipt_dscp.ko and ipt_DSCP.ko exists in /lib/modules/<kernel-version>/kernel/net/ipv4/netfilter/.

# ls /lib/modules/2.6.18-419.el5/kernel/net/ipv4/netfilter/ipt*|grep -i ipt_dscp*
/lib/modules/2.6.18-419.el5/kernel/net/ipv4/netfilter/ipt_dscp.ko
/lib/modules/2.6.18-419.el5/kernel/net/ipv4/netfilter/ipt_DSCP.ko

• In RHEL6, ipt_ecn.ko and ipt_ECN exists in /lib/modules/2.6.32-754.el6.x86_64/kernel/net/ipv4/netfilter/.

# ls /lib/modules/2.6.32-754.el6.x86_64/kernel/net/ipv4/netfilter/ipt*|grep -i ipt_ecn*
/lib/modules/2.6.32-754.el6.x86_64/kernel/net/ipv4/netfilter/ipt_ecn.ko
/lib/modules/2.6.32-754.el6.x86_64/kernel/net/ipv4/netfilter/ipt_ECN.ko

• What is the difference between these files?