Cisco AS5350/AS5350XM and AS5400/AS5400XM Gateways

The AS5350/AS5350XM is a 1U universal port access server with 3 expansion slots supporting 2 to 8 T1s or 7 E1s, and typically with single AC or DC power (Click here for a list of available AS5350 and AS5350XM power supplies). The original AS5350 has dual 10/100 ethernet and a 250MHZ CPU. DRAM configurations range from 128MB to 512BM, and Flash is normally 32MB or 64MB.

The AS5350XM version has dual 10/100/1000 ethernet and 750MHZ processor speed, with 512MB DRAM and 128MB Flash, plus the ability to perform as a softswitch (IP-to-IP voice switching). It also support Cisco's new PVDM2-based hardware (discussed in more detail below).

Both the AS5350 and AS5350XM can be provisioned with one or two 2, 4, or 8PRI trunk cards, or CT3 card, and one or two 60NP or 108NP DSP cards - the main limitation being that only three expansion slots are available. These cards are identical to those used in the AS5400.

The AS5350 shown here is configured with 8PRIs and 216 ports, can could be either the AS535-8T1-192-V or AS535-7E1-210-V. The AS5350XM supports Cisco's new high-complexity PVDM2-64 DSP modules (click PVDM2 tab selection above for details on this hardware), adding G.728 and Adaptive Multirate AMR-NB codec support to the AS5350, and increasing the AS5350's capacity to a full CT3.

Since the AS5350/AS5350XM has only 3 expansion slots, the processor-based limitations of the AS5400 series doesn't apply. A summary of AS5350/AS5350XM bundles is listed below. Models configured with 60NP and 108NP cards are listed first, followed by those with PVDM2 hardware.

For help in configuring an AS5350/XM access server, click here

The 2U AS5400 lines, consisting of the AS5400, AS5400HPX, and AS5400XM, are big brothers to the AS5350, with 7 expansion slots supporting from 2 to 24 PRIs or CT3/DS3 circuit, and dual AC or dual DC power. All three models can be provisioned with one or more 2, 4, or 8PRI trunk cards or CT3/DS3 card, and either one or more 60NP or 108NP DSP cards, or Cisco's newer AS5X-FC with PVDM2-64 hardware (for the XM model only). These cards are identical to those used in the AS5350, and are interchangeable.

Pictured left is an AS5400 with 16E1s and 480 ports. Using the traditional 60NP and 108NP cards, the maximum number of ports in any of the models is 648 - due to expansion slot limitations. All models are universal access servers, supporting voice, data, and fax, plus routing and transcoding in addition to origination and termination capabilities.

The standard AS5400's 250MHZ CPU limits the maximum number of functional VOIP ports to about 350 (and less for higher complexity codecs and SIP traffic, although it can handle 648 dialup ports without a problem) and the HPX's limit is about 480 ports, although these limits vary on the type of traffic. Those wanting to use the full 648 ports for VOIP, or to use the full 672 ports in a DS3 circuit, can use a stacked configuration to handle a full DS3 circuit using AS5400 chassis or move up to the XM versions of the AS5400.

The AS5400XM and AS5350XM are able to support Cisco's PVDM2 DSP hardware (described below) and are able to function both as IP-IP softswitch-type gateways and transcoding gateways (for example in converting G711 to G729).

Although the AS5400, AS5400HPX, and AS5400XM are virtually identical in terms of physical capabilities and specifications, their capabilities differ depending on CPU speed, plus the XM model line's ability to use PVDM2-based DSP hardware. The table below provides an overview of each model's practical capabilities.

For help in configuring an AS5400/XM access server, click here

Model Comparison - AS5400, AS5400HPX, and AS5400XM	Maximum Useable Voice Ports	CPU Speed	Features
AS5400	380 (depending on use), 672 with stacked configuration.	250 MHZ	2 FE, for use above 300 ports consider stacking
AS5400HPX	480 (depending on use), 672 with stacked configuration.	397 MHZ	2FE, for use above 450 ports consider stacking
AS5400XM	672 (with PVDM2 hardware)	650 MHZ	2GE, supports softswitch capabilities. With PVDM2 hardware, the XM supports narrowband (GSM) Codecs, and enhanced transcoding.

AS5400 Stacking

It is known that the base AS5400 can support up to about 384 ports of voice traffic before running out of processor resources. Even the faster HPX can only handle about 480 ports maximum. The AS5400XM was developed by Cisco to address this limitation. However, even with the AS5400XM, the traditional DSP hardware only allowed a maximum of 648 ports - not the 672 ports in a full DS3 circuit. So Cisco also developed newer PVDM2 hardware that enabled the AS5400XM to handle a full 672 ports of traffic. The street price of this solution, when configured to support G729 and lower Codecs, is above $50,000.

Here an affordable alternative is possible. It consists of two stacked, DRAM-maxed AS5400s, one with 2 CT3 cards and 324 ports, the second with 1 CT3 port and 384 ports. It works like this - for origination work the first unit brings in the external DS3 ciruit on its first CT3 card. Part of the traffic is processed on its 324 universal DSPs, and the rest is sent out on its second CT3 into the 2nd AS5400s only CT3 card. The 2nd AS5400 then processes the remainder of the calls. Each unit sends the voip traffic out via its fast ethernet ports. For termination work, the process is similar but in reverse. This configuration provides great performance and redundancy by spreading the traffic over two complete units - although not comparatively tested, it could even better than the AS5400XM, at a fraction of the cost.

AS5400 Stacking for Reverse Mux Operations: Other stacking configurations could include a second unit that routes out multiple E1/T1 PRIs. Contact us for details and a price quote.

The most recent additions to the AS5400XM and AS5350XM lines are the HC, MC, and LC/HD versions (high complexity, medium complexity, and low complexity/high density). They use a new carrier card, the AS5X-FC and the new PVDM2-64 DSPs. This DSP is capable of supporting high complexity codes, and in particular two that are not supported on the 60np and 108np cards - G.728 and Adaptive Multirate AMR-NB narrowband for wireless phone-type applications.

The number of simultaneous voice ports varies, depending on the complexity of the CODEC, because higher complexity codecs consume more voice resources on the PVDM2-64. With the lowest (LC) complexity codec (G711), which Cisco also refers to as high density (HD), each PVDM2-64 supports 64 voices.

Medium complexity (MC) codecs support 32 voices, and high complexity (HC) codecs supports 24. So, for example, if your environment is one using 100% G729 traffic (medium complexity) and you have 8T1s of traffic, then you would need 8 x 24 or 192 total ports, and 192 x 2 (2 because medium complexity codecs cut the PVDM2-64's resources in half), or 384 total PVDM2-64 resources.

Since each PVDM2 has 64 base channels, 384/64=6 - you would need 6 PVDM2-64 modules to support the 8T1 G729 gateway. More
information from Cisco on PVDM2 capabilities is here. Up to six PVDM2 DSPs can be loaded on the AS5X-FC carrier card, and this increased density also gives the AS5400XM and AS5350XM the ability to handle - for the first time - a full 672 ports in a DS3 circuit, and up to 24 E1s or T1s, in a single unit.

The combination of the AS5400XM or AS5350XM along with this new PVDM2 hardware is an excellent combination for advanced transcoding, softswitch operations, and high-end origination/termination work. From a cost perspective, certain AS5350XM and AS5400XM configurations may be more economical than by using the traditional 108np/60np hardware - particularly in a G711-only environment, and for the AS5350XM 4E1 120 configuration. Contact us for a more detailed explanation.