GateD Intermediate System to Intermediate System (IS-IS)

Green Hills Software's GateD IS-IS (Intermediate System to Intermediate System) module is the most advanced implementation of IS-IS available. The IS-IS module was designed from the ground up to include all of the latest functionality and was specifically engineered for operation in an IP environment.

IS-IS is one of the premier products in the GateD commercial family of routing protocols. IS-IS contains all the functionality necessary for use in a carrier class router or switch. It has Level 1 and Level 2 routing, allows use of a default routing metric, and has support for equal cost, multi-path routing. Further, our IS-IS is directly expandable to handle IPv6 routing, using the IS-IS Extensions for IPv6 module from Green Hills Software.

Due to technical limitations at the time, the ISPs who were around at the beginning of the Internet chose IS-IS over OSPF for their IGP. Though those technical limitations no longer exist today, those ISPs have become today’s tier 1 carriers. As a result, any box that is targeted as a tier 1 carrier must have IS-IS.

Additionally, new applications being developed today function better from a technical perspective with IS-IS than they do with OSPF. In some cases, this may have to do with the nature of the network being constructed. For example, companies that deploy under certain, very distributed topologies, such as exchange points, have chosen IS-IS as their IGP. In other cases, IS-IS is being used outside of the scope of the general Internet. For example, because of its focus on the link rather than the interface, IS-IS makes perfect sense for establishing optical cross connects inside an all-optical network. Finally, with space and processing power at a premium, IS-IS’s ability to run simultaneously in an IPv4 and IPv6 environment (with Green Hills Software's IS-IS for IPv6 extensions), can be the perfect choice when targeting IPv6 rich environments, which is increasingly important in the global economy.

Speed
Green Hills’ IS-IS, like OSPF, has been highly optimized with patent pending enhancements to improve the speed of the SPF. Tests have shown one-second convergence times for networks approaching 10,000 nodes (almost a full order of magnitude bigger than the largest IS-IS networks in the world today). This is due to a very fast, proprietary SPF implementation and optimized packet processing.

Elegance
The IS-IS protocol was designed from the beginning to be highly extensible. Green Hills kept this in mind when writing IS-IS. The implementation supports only the address families in widespread use in the Internet today. As a result, the code path is exceptionally clear and readable. Further, functionality is neatly divided among 39 “c” and “h” files. When new functionality has appeared, such as the addition of traffic engineering extensions or constraint-based routing calculations, the modifications to the code have been exceptionally clear, along with the points of interaction between source files.

Traffic engineering and CSPF
One of the most recent additions to Green Hills’ IS-IS module is support for traffic engineering extensions. The GateD code includes not only the latest extensions specified by the IETF, but also a proprietary constraint-based SPF calculation to make use of the data passed around by these extensions. A straightforward API gives outside applications direct accessibility to both the data and the calculation of constrained paths.

Better bottom line
For certain applications, such as voice-over-IP, millisecond timer granularity is a requirement. But even in a classical IP setting, Green Hills Software's MULTI compile-time options let customers choose footprint and speed optimizations that result in substantial bottom-line savings, by reducing memory requirements and processing power at any given point in time. And by using Green Hills complete routing and switching bundles that are pre-tested and validated together, customers achieve maximum time to market benefits while increasing system reliability and availability.

Reduced on-going support costs
Over time, the Internet has grown, increasing the demand for new features, and the specifications have been revised to add support for those new features. But once a router box is deployed in the field, there’s a strong resistance to changing working code. The elegance and distribution of Green Hills’ IS-IS implementation make the tough decisions easier. As new features are delivered, the points of interaction are exceptionally clear, dramatically reducing the load on a QA department before releasing the code. In addition, protocols are thoroughly tested and validated with Green Hills’ INTEGRITY operating system and GHNet routing stack, providing customers integrated solutions enabling significant reductions in the time and cost to add to or update existing deployed systems.

GateD’s platform independent scalable software has been ported, tested and validated on Green Hills secure INTEGRITY operating system and GHNet IPv4/v6 router stack, providing end customers with a complete, functional single-vendor solution.

For pre-integrated reference platform or commercial platform support or operating system support other than INTEGRITY, please contact Green Hills Software (gated-info@ghs.com).

• RIPng
• BGP
• OSPF
• OSPF3
• BGP
• MP-BGP Extensions for IPv6
• MP-BGP for Multicast
• CLI

• VRRP
• PIM-DM
• PIM-SM
• PIM-SSM
• DVMRP
• MSDP
• Layer 2 Switching
• SNMP v1/2c/3

• INTEGRITY Operating System
• INTEGRITY Secure Virtualization
• GHNet IPv4/v6 host and routing stack
• SSH, SSL/TLS, IPSec/IKE, crypto algorithms
• Telnet, RADIUS, SNTP, DNS, DHCP
• Wireless Supplicant with security and CCX