Dave, The quick answer, no, you will not need the 37xx series to prepare for the CCIE R&S exam.
The long answer, to see what features are unique to an image, platform, or release, use the feature navigator located at http://www.cisco.com/go/fn Here's the output of a 3640 running 12.2(15)T7 (latest 12.2T train) vs a 3725 running 12.2(15)T7, both feature sets are Enterprise Plus. The features unique to the 3725 are as follows: Auditing Raw Buffers on a Channel Associated Signaling Interface BGP Increased Support of Numbered as-path Access Lists Cisco Discovery Protocol (CDP) over ATM CNS Flow-Through Provisioning Contact Closure Network Module DHCP Accounting DHCP Server - On Demand Address Pool Manager DHCP Server - Option to Ignore all BOOTP Requests DTMF Relay for SIP Calls Using Named Telephone Events (NTE) Enhanced Debug Capabilities for Cisco Voice Gateways Enhanced G.168 Echo Cancellation Enhanced Packet Marking Frame Relay PVC Bundles with IP QoS Support Frame Relay PVC Bundles with MPLS QoS Support G.SHDSL Symmetric DSL Support Gateway Support for Advanced Busy Out for Gatekeeper Registration Globalized Cadence and Tone for Cisco IOS Gateways H.323v4 - Enhanced Call Usage Reporting IPv6 Provider Edge Router over MPLS L2TP Redirect MGCP support for CallManager (IP-PBX) MPLS LDP - MIB Notifications MPLS VPN - MIB Notifications MS-CHAP Version 2 Multicast-VPN: Multicast Support for MPLS VPN MultiNode Load Balancing (MNLB) Forwarding Agent NAT Integration with MPLS VPNs QSIG Backhaul (TCP based) for Cisco IOS Gateways RADIUS EAP Support Session Limit Per VRF SIP Gateway Support of 'tel' URL SIP Gateway Support of RSVP SIP Transfer Using the Refer Method and Call Forwarding SLB (Server Load Balancing) SLB: Alternate IP Addresses SLB: Automatic Server Failure Detection SLB: Automatic Unfail SLB: Bind ID Support SLB: Client-Assigned Load Balancing SLB: Delayed Removal of TCP Connection Context SLB: Dynamic Feedback Protocol (DFP) SLB: Maximum Connections SLB: Port-Bound Servers SLB: Server NAT SLB: Slow Start SLB: Stateless Backup SLB: Sticky Connections SLB: SynGuard SLB: TCP Session Reassignment SLB: Weighted Least Connections SLB: Weighted Round Robin SRST: Survivable Remote Site Telephony Version 1.0 Subscriber Service Switch VoiceXML For Cisco IOS VoiceXML Transfer Enhancements VoiceXML Voice Store and Forward VoIP Trunk Group Label Routing Enhancement VPDN Default Group Template VPDN Multihop by DNIS AAA Resource Accounting AAA-PPP-VPDN Non-Blocking Accounting of VPDN Disconnect Cause ACL Default Direction Clear Channel T3/E3 with Integrated CSU/DSU Connect-Info RADIUS Attribute 77 Distributed Director - Multiple DNS record Distributed Director - Multiple port test Distributed Director - Syslog Info Distributed Management Event MIB Persistence DNS Server Support for NS Records Enhanced Test Command Fast Fragmentation (Fast-Switched Fragmented IP Packets) Fax Relay Packet Loss Concealment Frame Relay 64-bit Counters FUNI Support for Routers HSRP support for MPLS VPNs ICMP ECHO-based RTT probing by DRP agents Interactive Voice Response (IVR) Version 2.0 IP Precedence Accounting IP to ATM CoS, per-VC WFQ and CBWFQ ISDN Advice of Charge (AOC) LANE dCEF LANE Optimum Switching MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles MGCP Based Fax (T.38) and DTMF Relay MGCP VoIP Call Admission Control MGCP VoIP Signaling Modem over BRI MPLS over ATM: Virtual Circuit (VC) Merge MPLS Scalability Enhancements for LSC and ATM LSR MPLS Traffic Engineering (TE) - Automatic bandwidth adjustment for TE tunnels MPLS Traffic Engineering (TE) - OSPF Support MPLS VPN - OSPF PE-CE Support Multilink PPP Enable/Disable via Radius for Preauthentication User Multiprotocol over ATM (MPOA) Multiprotocol over ATM for Token Ring (MPOA) Offload Server Accounting Enhancement PPP over ATM (IETF-Compliant) PPPoA/PPPoE autosense for ATM PVCs PPPoE over Gigabit Ethernet interface PPPoE Session limit Preauthentication with ISDN PRI and Channel-Associated Signalling Enhancements RADIUS Attribute 66 (Tunnel-Client-Endpoint) Enhancements RADIUS Attribute Value Screening RADIUS Progress Codes RADIUS Tunnel Attribute Extensions Redundant Link Manager (RLM) Remote Source-Route Bridging (RSRB) Resource Pool Management with Direct Remote Services RFC 1483 for Token Ring Networks RSVP - ATM Quality of Service (QoS) Interworking Service Assurance Agent (SAA) Distribution of Data Service Assurance Agent (SAA) History Statistics Service Assurance Agent (SAA) ICMP Echo Operation Service Assurance Agent (SAA) ICMP Path Echo Operation Service Assurance Agent (SAA) Reaction Threshold Service Assurance Agent (SAA) Scheduling Operation Service Assurance Agent (SAA) SNA LU2 Echo Service Assurance Agent (SAA) TCP Connect Operation Service Assurance Agent (SAA) UDP Echo Operation Stream Control Transmission Protocol (SCTP) T.37/T.38 Fax Gateway Token Ring LANE Trimble Palisade NTP Synchronization Driver Turbo Flooding of UDP Datagrams UDLR Tunnel ARP and IGMP Proxy V.92 Modem on Hold Voice over IP Q.SIG Network Transparency X.25 on ISDN D-Channel HTH, Brian McGahan, CCIE #8593 [EMAIL PROTECTED] Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-334-8987 Direct: 708-362-1418 (Outside the US and Canada) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave Williams Sent: Thursday, September 04, 2003 1:00 PM To: [EMAIL PROTECTED] Subject: 2600 3600 3700 series routers [7:74812] Group, I'm currently studying for the CCIE lab exam. My lab consists of 2500 - 2600 series routers. My question is if there is a difference in IOS features between the 3600s and the 3700s. I'm trying to decide if I need some rack time playing around with the 3700s or if the 2600s and 3600s will do everything the 3700s will do. Thanks, dave **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74820&t=74812 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html