Cisco 2901

Cisco 2911

Cisco 2921

Cisco 2951

Services and Slot Density

Embedded Hardware-Based Cryptography and Acceleration

Yes

Yes

Yes

Yes

Cisco Unified SRST Sessions

35

50

100

250

Cisco Unified CCME Sessions

35

50

100

150

Total Onboard WAN 10/100/1000 Ports

2

3

3

3

RJ-45-Based Ports

2

3

3

3

SFP-Based Ports (use of SFP port disables the corresponding RJ-45 port)

0

0

1

1

Service Module Slots

0

1

1

2

Double-Wide Service Module Slots (use of a double-wide slot will occupy all single-wide service module slots in a 2900)

0

0

1

1

EHWIC Slots

4

4

4

4

Double-Wide EHWIC Slots (use of a double-wide EHWIC slot will consume two EHWIC slots)

2

2

2

2

ISM Slots

1

1

1

1

Onboard DSP (PVDM) Slots

2

2

3

3

Memory DDR2 ECC DRAM - Default

512 MB

512 MB

512 MB

512 MB

Memory (DDR2 ECC DRAM) - Maximum

2 GB

2 GB

2 GB

2 GB

Compact Flash (External) - Default

slot 0: 256 MB

slot 1: none

slot 0: 256 MB

slot 1: none

slot 0: 256 MB

slot 1: none

slot 0: 256 MB

slot 1: none

Compact Flash (External) - Maximum

slot 0: 4 GB

slot 1: 4 GB

slot 0: 4 GB

slot 1: 4 GB

slot 0: 4 GB

slot 1: 4 GB

slot 0: 4 GB

slot 1: 4 GB