MSR 2003 routing/capabilities

[padair]

I am working on upgrading a network that currently uses a Cisco ASA 5505 for the WAN device/firewall/Site-to-Site VPNs.  The network has multiple internal subnets and there is a Cisco 2621 that handles the internal subnet routing and anything external it passes to the ASA 5505.  Everything works great, except the internet service for this network was upgraded to 100mbps fiber symetrical and now the Cisco 2621 gets overrun interface errors all day long.  Any speed past about 40mbps I figure exceeds the 25kpps routing capabilities.

I'd like to replace both devices with a single device that can handle the firewalling, VPN's and also internal subnet routing.  I've tried doing this all with an ASA but the internet subnet routing is a PITA.  I was thinking a Cisco ISR 4331 would do the trick but then I came across HP's MSR line.  There is also a tricky NAT/PAT config on the ASA I want to make sure an MSR 2003 can handle.  Phone service is delivered thru SIP trunks thru the internet that is secured by access-list from the provider.  The internet service comes with 5 usable IPs.  We assign one fo the IP's to for phone switch operations.  The phone switch has 3 private ip's.  Call them x.x.x.1 and x.x.x.2.  When any of those 3 ip's route out to the internet they have their out outbound NAT rule and show up as y.y.y.y on the internet.  The service providing the SIP trunks point all traffic for our service to the y.y.y.y address.  The ASA then looks at the traffic and if it is SIP udp or tcp on port 5060 it will route that internally to x.x.x.1.  If it is on any of the audio ports (UDP range 20000 to 49999) it will route those internally to x.x.x.2.

Before purchasing an MSR2003 I want to make sure it can handle this type of inbound routing where 1 public IP can come inbound to separate internal ip's dependant on the traffic type.

Any advice appreciated.

thx.