Cisco Router ISR 2900

About the Cisco 2900 Series ISR

The Cisco 2900 Series Integrated Services Routers are the modular branch platform that sits between the small ISR 1900 and the larger ISR 3900. Four chassis make up the range — the 2901, 2911, 2921 and 2951 — and each one is built around the same idea: a fixed set of Gigabit Ethernet WAN ports, four Enhanced High-Speed WAN Interface Card (EHWIC) slots, Service Module (SM) slots for larger cards, and Packet Voice DSP Module (PVDM3) slots for voice.

Because the platform is modular, the same chassis is sold in a number of service bundles. Each bundle arrives with a different set of features already licensed, and the bundle is written into the part number. Buying the bundle that matches what the site has to do is materially cheaper than licensing the base chassis afterwards. The bundles you will see on this page are:

• Base (CISCO2901/K9) — the router on its own, no voice or security licence pack.
• SEC — adds a Security Licence PAK for IOS firewall, IPsec VPN and zone-based firewall features.
• V — voice bundle: a PVDM3 voice DSP module plus a Unified Communications Licence PAK.
• VSEC — voice and security licensing on one chassis.
• VSEC-SRE — as VSEC, plus a Services Ready Engine module (SRE 300 on the 2901, SRE 700 on the larger platforms) for hosting applications inside the router.
• CME-SRST — voice bundle with CallManager Express and Survivable Remote Site Telephony licensing (FL-CME-SRST-25) for up to 25 phones.
• VSEC-CUBE — VSEC plus a Cisco Unified Border Element session licence (FL-CUBEE-25) for SIP trunk termination.
• HSEC+ — high-security bundle with a VPN Internal Service Module for hardware-accelerated encryption.
• WAASX — Wide Area Application Services Express: WAN optimisation performed by the router's own IOS image, with no service module required.
• WAAS-SEC — WAN optimisation delivered by a Services Ready Engine module (SRE 700 or SRE 900) combined with a security licence pack.

All four platforms run the same IOS software family, so choosing between them comes down to port and slot count, voice scale, and how much WAN optimisation or services-engine capacity the branch actually needs.

How to Choose a Cisco 2900 Series Router

1. Platform: 2901, 2911, 2921 or 2951?

The four chassis differ mainly in port count and expansion room:

• 2901 — 2 x GE WAN, 4 EHWIC, 2 DSP, 1 SM. The entry point; suitable for a small branch running data and a modest voice deployment.
• 2911 — 3 x GE WAN, 4 EHWIC, 2 DSP, 1 SM. A third Gigabit port and more memory headroom than the 2901.
• 2921 — 3 x GE WAN, 4 EHWIC, 3 DSP, 1 SM. The extra DSP slot matters when voice transcoding or conferencing grows.
• 2951 — 3 x GE WAN, 4 EHWIC, 3 DSP, 2 SM. The largest of the four, with a second service-module slot for WAN optimisation or application hosting.

As a rule: pick by slot count first, and by voice scale second. The 2951's second SM slot is what allows the S-SRE-WAE configuration, which pairs an SRE 700 module with an NME WAE 502 accelerator card in the same chassis.

2. Which service bundle?

Match the suffix to what the site must do now — not to what it might do later:

• Data routing only → base model
• Site-to-site VPN or zone-based firewall → SEC
• IP telephony at the branch → V (or CME-SRST if the router runs call control itself)
• Voice and security together → VSEC
• Voice, security and on-router applications → VSEC-SRE
• SIP trunking to a provider → VSEC-CUBE
• Hardware-accelerated encryption for a VPN concentrator role → HSEC+

3. Do you need a WAAS bundle?

WAAS addresses a specific problem: a branch with a slow or congested WAN link serving users who pull the same data repeatedly. There are two shapes of it in this series:

• WAASX runs in the IOS image itself. There is no extra hardware, which makes it the cheap way to try WAN optimisation — but it consumes router CPU and memory.
• WAAS-SEC moves the optimisation onto a Services Ready Engine module (SRE 700 on the 2911 and 2921, SRE 900 on the 2951) and adds a security licence pack. The engine carries the load instead of the router.

The WAAS Enterprise tier in these bundles scales with the platform: Small on the 2911, Medium on the 2921 and Large on the 2951. If the branch does not have a repeat-data problem, none of this is worth paying for.

4. Check the power supply variant

The 2911 is available in a DC version (CISCO2911-DC/K9) alongside the standard AC models. In a telecoms cabinet or a site with a -48 V DC plant, that is the part number to order; it saves an external AC rectifier.

Cisco 2900 Series Model Comparison

2901 platform — 2 x GE · 4 EHWIC · 2 DSP · 1 SM

2911 platform — 3 x GE · 4 EHWIC · 2 DSP · 1 SM

2921 platform — 3 x GE · 4 EHWIC · 3 DSP · 1 SM

2951 platform — 3 x GE · 4 EHWIC · 3 DSP · 2 SM

Prices are our current selling prices in US dollars, excluding shipping. Click a model number for the full specification table and availability. Two CME-SRST models are quoted on request — send us the quantity and destination and we will price them the same day.

Frequently Asked Questions

What is the difference between the 2901, 2911, 2921 and 2951?

Port count and expansion room. The 2901 has 2 x GE WAN, 2 DSP slots and 1 SM slot. The 2911 and 2921 both have 3 x GE WAN and 1 SM slot, but the 2921 adds a third DSP slot for voice. The 2951 is the only one of the four with two service-module slots, which is what lets it run an SRE module and a WAN accelerator card at the same time.

How do I tell which service bundle a router includes?

From the part number suffix. -V is a voice bundle, -SEC a security licence pack, -VSEC both, -VSEC-SRE adds a Services Ready Engine, -CME-SRST adds CallManager Express and SRST licensing for 25 phones, -VSEC-CUBE adds a Unified Border Element licence, HSEC+ adds a VPN Internal Service Module, and WAASX / WAAS-SEC indicate the WAN optimisation bundles. A model with no suffix is the base platform.

What does the WAAS Express bundle actually give me?

WAAS Express performs WAN optimisation — compression, deduplication and TCP acceleration — using the router's own IOS image, with no extra hardware. On these configurations the router is also supplied with maximum memory, because that is what the feature consumes. It is the cheapest way into WAN optimisation, but it does compete with the router for CPU and memory.

When should I choose WAAS-SEC instead of WAASX?

When the optimisation load should not sit on the router, or when you need the security licence pack anyway. WAAS-SEC puts the optimisation on a dedicated Services Ready Engine module — SRE 700 on the 2911 and 2921, SRE 900 on the 2951 — and bundles the corresponding WAAS Enterprise tier (Small, Medium or Large) with a security PAK.

Do the voice bundles include a DSP module?

Yes. The V, VSEC, VSEC-SRE, VSEC-CUBE and CME-SRST bundles all ship with a PVDM3 voice DSP module — PVDM3-16 on the 2901 and 2911, PVDM3-32 on the 2921 and 2951 — which provides the conferencing and transcoding resources the voice features need. The base, SEC and HSEC+ models do not include one.

Can I run voice and security on the same chassis?

Yes — that is exactly what the VSEC family is for. VSEC gives you voice and security licensing together, VSEC-SRE adds on-router application hosting, and VSEC-CUBE adds a Unified Border Element session licence for connecting to a SIP trunk provider.

Is there a DC-powered version?

Yes. CISCO2911-DC/K9 is the 2911 with a -48 V DC power input, for cabinets and sites that already have a DC plant. The other three platforms in this series are AC only.

Do you supply the EHWIC, SM and PVDM3 modules separately?

Yes. Tell us the router model and the interface mix you need — WAN cards, switching modules, voice cards or DSP modules — and we will quote the complete configuration rather than just the chassis.