Cisco Cisco IOS Software Release 12.0 S

router will be connected to 100 or more remote routers. In a hub and spoke topology, the remote router 
must forward all nonlocal traffic to a distribution router, so it becomes unnecessary for the remote router 
to hold a complete routing table. Generally, the distribution router does not need to send anything more 
than a default route to the remote router.

see the following document for further information:

 

Platforms: Cisco 7200 series, Cisco 7500/RSP series, Cisco 12000 series

The Filtering Inter-Area Routes on an ABR feature extends the ability of an area border router (ABR) 
that is running the OSPF protocol to filter type 3 link-state advertisements (LSAs) between different 
OSPF areas. This feature allows only specified prefixes to be sent from one area to another area while 
restricting all other prefixes. This type of area filtering can be applied out of a specific OSPF area, into 
a specific OSPF area, or into and out of the same OSPF areas at the same time. This feature is supported 
by the addition of the area filter-list command.

Platform: Cisco 12000 series

Cisco IOS Release 12.0S now provides Internet Control Message Protocol (ICMP) and Per Interface 
Rate Control (PIRC) on 3-Port Gigabit Ethernet line cards. 

The ICMP rate limiting on Engine 2 Packet-over-SONET (POS) line card feature is used to rate-limit 
ICMP echo-reply traffic in order to protect hosts against Denial of Service (DoS) attacks. Per Interface 
Rate Control (PIRC) controls the input access rate on a single physical interface on the Engine 2 
packet-over-SONET (POS) line cards. 

see the following documents for further information:

Platform: Cisco 12000 series

Cisco IOS Release 12.0S now provides Weighted Random Early Detection (WRED)/Modified Deficit 
Round Robin (MDRR) support on 3-Port Gigabit Ethernet line cards in both the ingress and egress 
directions.