Taking a cursory look at new features in Cisco IOS 12.4

Enterprise Networks & Servers, Sep 2005 by Welcher, Peter J

I'm writing this in mid-August. Things have been hot (business, weather). That means its time for my more-or-less annual article about new features in Cisco IOS. I'm going to mainly cover Cisco IOS 12.4. The features in PIX 7.0 are also very interesting, but will have to be another whole article.

My intent here is to call attention to features I think are interesting, amazing, neat or just plain useful. There is no way this article can be complete (hey, I do have a full-time job, despite what some of you think about consultants... that stuff about living a life of luxury!). So I'll refer the curious to the Cisco online documents for the entire set of new features.

About Release 12.4

The mainline or non-T release accumulates features in the 12.3 T and "letter" releases. New features will be added to the 12.4 T train of releases, whereas 12.4 mainline is for bug fixes. Thus new features for the 12.4 mainline code is really describing features added at some point in 12.3, ones that may be approaching the maturity required for production use. Note that I am not implying you should be running 12.4 code in production yet, just anticipating that you will probably be doing so at some point, after more of the bugs are fixed. I do have a customer already running 12.4 code in production - due to a need for hardware support. Most sites will probably wait a while.

The cumulative new features list can be found at http:// www.cisco.com/en/US/products/ps6350/prod_release_ notes_list.html as a Release Note. Or off the http://www. cisco.com/go/ios page, aka http://www.cisco.com/warp/ public/732/. If you click on "Cisco IOS Software Major Release 12.4" you'll see links to the new features Bulletin.

New features rolled into 12.4 mainline

The Bulletin at http://www.cisco.com/en/US/products/ ps6350/prod_bulletin09186a0080457b39.html provides the info about new features rolled up into 12.4. The following attempts to summarize and call attention to items that have caught my eye. To find the details that were necessarily omitted below, consult this document!

The 12.4 new features document lists the following broad areas of new features:

* Hardware support

* Broadband

* High availability

* Infrastructure

* IP Mobility

* IP Multicast

* IP Routing

* IP Services

* IPv6

* Management Instrumentation

* MPLS

* QoS

* Security and VPN

* Voice

Let's take a look at some of the new features in these categories.

The list of new hardware support accumulated into 12.4 is impressive. It includes NAM for modular routers, the new ISR routers, Cisco Unity Express, IDS Network Module. The engineers have stayed busy!

Broadband encompasses DSL aggregation features, ties to MPLS, enhanced dial-like features, that sort of thing. Interesting but a bit specialized?

High availability is two features: Cisco IOS Warm Upgrade and Cisco IOS IPsec stateful Failover. In Warm Upgrade, you decompress and load IOS to memory, greatly speeding the boot process in switching over. The new image need not be burned to flash to do this. You do need sufficient RAM to decompress the new image.

Infrastructure is two items: Cisco IOS Embedded Event Manager 2.1 and Embedded Resource Manager (ERM). The former is the surrounding framework for TCL in IOS. See also my previous article file:///C:/html/html.dir.nc/ welcher/papers/iostc101.html. The idea is to detect events and then trigger local actions within the router, namely any CLI command(s). ERM allows monitoring of internal resources, plus the "ability to perform actions to improve performance and availability of the device," and "yields information to allow better understanding of scalability requirements" (resource consumption). They even say those IBM words, "autonomic computing."

IP Mobility: support for Mobile IP through NAT (RFC 3519), some other Mobile IP enhancements, and Dynamic security Associations and Key Distribution (i.e. Mobile IP SAs no longer have to be statically configured in advance). IP Multicast includes some IPv6 multicast features, MSDP enhancements per IETF MSDP Draft 20, and PIM Dense Mode Fallback Prevention after RP Loss. I'll skip over IPv6 as not being of general interest (with apologies to those in DoD or government agencies). The PIM-DM Fallback Prevention feature I like, because my feeling for quite a while has been that one should engineer multicast to avoid PIM-DM even with RP loss. RP-of-last-resort and other techniques have allowed this for a while, but it will be nice as a safety measure to be able to tell the router to never revert to Dense Mode.

One would expect IP Routing to be an area with many new features. One minor goodie is that routemap display via show commands now includes more ACL details.

Optimized Edge Routing (OER) is an interesting new feature that may be the subject of a future whole article in itself. OER is technology for determining best outbound route, usually when one has two or more ISPs. It is based on NetFlow and SAA. OER can dynamically detect path failures at the WAN edge. "... Cisco OER is unique in that it can make instant routing adjustments based on criteria other than static routing metrics: response time, packet loss, path availability, traffic load distribution, and financial cost minimization policies."