Cisco WS-X4648-RJ45V-E Full Official Technical Specification Document

1. Product Overview

Official Full Designation

Cisco WS-X4648-RJ45V-E is theCatalyst 4500E Series 48-Port Gigabit RJ45 IEEE 802.3af PoE Hot-Swappable Line Card, a Generation 46 oversubscribed copper PoE modular interface card exclusively designed for Catalyst 4500E-series modular chassis and only operable with E-series supervisor enginesCisco. It delivers 10/100/1000BASE-T copper switching with native IEEE 802.3af PoE (15.4W per port) and backward compatibility with Cisco pre-standard inline PoE, optimized for enterprise campus access layer wiring closets, IP phone aggregation, low-power enterprise Wi-Fi APs, fixed HD IP surveillance cameras, and desktop endpoint power-and-data transportCisco.

Core Definition: Single-slot hot-swappable Catalyst 4500E line card equipped with 48 independent auto-sensing Gigabit RJ45 ports, providing 24 Gbps per-slot shared switching capacity (2:1 oversubscribed forwarding architecture)Cisco. It only supportsIEEE 802.3af PoE (max 15.4W per port)(unlike WS-X4648-RJ45V+E which supports PoE+ 30W), backward compatible with legacy Cisco pre-standard PoE powered devices, IEEE 802.3az Energy Efficient Ethernet (EEE), jumbo frames up to 9216 bytes, hardware QoS scheduling, Layer 2 switching and hardware-assisted lightweight Layer 3 IPv4 routing, full Catalyst IOS/IOS XE enterprise security and unified communications feature compatibility.

SKU Naming Breakdown

1. WS-X: Cisco modular switch line card / supervisor module product series prefix
2. 46: E-series base performance line card family for Catalyst 4500E chassis (2:1 oversubscribed fabric)
3. 48: Total physical port quantity on the card (48 Gigabit RJ45 copper ports)
4. RJ45: Port media type – 10/100/1000BASE-T twisted-pair copper RJ45 interfaces
5. V: PoE-capable inline power line card (IEEE 802.3af standard only)
6. E: E-series enhanced hardware architecture;only compatible with Catalyst 4500E chassis and E-series supervisors(incompatible with non-E legacy 4500 chassis/supervisors)Cisco.

Product Lifecycle Notice

• Official Global Release Year: 2007
• End-of-Sale (EoS) Announcement Date: Cisco ceased manufacturing and new unit shipments
• Minimum Supported IOS Version: Classic IOS SG train 12.2(40)SG; IOS XE minimum release 3.5.0ECisco Russ...
• End of Software Maintenance: No new feature IOS/IOS XE releases post-EoS; limited critical security patch support expired
• Final End-of-Support (EoSS) Date: Cisco formal hardware repair and TAC engineering support fully terminated
• Legacy Status: All datasheets, installation guides, IOS/IOS XE configuration manuals are archived on Cisco’s legacy networking documentation portal; only third-party refurbished hardware and limited best-effort support are available.

Supported Chassis & Supervisor Compatibility

Compatible Catalyst 4500E Chassis

• WS-C4503-E (3-slot)
• WS-C4506-E (6-slot)
• WS-C4507R-E / WS-C4507R+E (7-slot redundant supervisor)
• WS-C4510R-E / WS-C4510R+E (10-slot redundant supervisor)

Critical Hardware Restriction

This line cardcannot operate with non-E legacy supervisors (WS-X4013, WS-X4013+), even when inserted into E-series chassis; E-series supervisor engines (II-Plus-E, IV-E, V-E, 8-E) are mandatory for normal operation.

Standard Factory Complete Bundle Contents

Each factory-sealed WS-X4648-RJ45V-E retail package contains all hardware and accessories required for chassis deployment:

1. WS-X4648-RJ45V-E hot-swappable line card module
2. Chassis mounting retention screws for secure slot installation
3. Quick-start hardware installation guide for line card insertion/removal and PoE power configuration
4. Global regulatory compliance, safety, and electromagnetic interference (EMI) certification documentation packet

Supported Software & Enterprise Deployment Architectures

Compatible Cisco IOS Software

WS-X4648-RJ45V-E supports two official OS branches for Catalyst 4500E platforms:

1. Classic IOS SG train: Minimum release 12.2(40)SG and all subsequent maintenance SG releases
2. IOS XE train: Minimum release 3.5.0E and all later IOS XE E-series releases Modern standalone IOS-XE switches and Catalyst 9000 series firmware are not compatible with this 46-series oversubscribed line card.

Supported Deployment Architectures

1. Enterprise Campus Access Layer Wiring Closet Aggregation Deployed in 4500E access layer switches to provide high-density copper PoE ports for end-user devices, including Cisco enterprise IP phones, single-radio low-power wireless access points, fixed HD IP surveillance cameras, and desktop PCs, supporting converged voice, wireless, video, and data traffic with full enterprise security feature support.
2. Unified Communications Voice Endpoint Aggregation IEEE 802.3af PoE power delivery for full line of Cisco enterprise IP phones, integrated with CUCM voice VLAN auto-detection and hardware QoS prioritization for low-latency VoIP media streams.
3. Low-Density Wireless LAN Aggregation 15.4W PoE power output supports single-radio enterprise Wi-Fi access points, eliminating separate AC power adapters for wireless infrastructure endpoints.
4. Converged Fixed IP Surveillance Camera Aggregation PoE power delivery for fixed HD IP security cameras deployed across campus buildings, with port security and private VLAN features to isolate untrusted edge camera endpoints from core corporate networks.

Core Integrated Functional Capabilities: 24 Gbps per-slot shared switching capacity (2:1 oversubscribed fabric), 48-port 10/100/1000BASE-T copper forwarding, native IEEE 802.3af PoE (15.4W max per port) + backward compatible Cisco pre-standard inline power, IEEE 802.3az Energy Efficient Ethernet, Layer 2 802.1Q VLAN trunking, jumbo frame support up to 9216 bytes, per-port hardware QoS scheduling with 4 egress queues per port, IGMP v1/v2/v3 hardware snooping, EtherChannel/PAgP/LACP link aggregation, UDLD unidirectional link detection, broadcast/multicast storm control, private VLANs, hot-swappable module design, and full interoperability with Catalyst 4500E unified communications and enterprise security feature sets.

2. Hardware & Performance Specifications

Core Switching & Forwarding Performance

• Per-Slot Switching Fabric Capacity: 24 Gbps shared memory architecture (2:1 oversubscribed design for 48 Gigabit ports)
• Port Buffer Allocation: Dedicated receive buffer per RJ45 port, shared egress buffer pool with Dynamic Buffer Limiting (DBL) congestion avoidance
• Forwarding Performance: Wire-speed Layer 2 switching for all 48 ports under non-oversubscribed load; hardware-assisted Layer 3 IPv4 forwarding, IPv6 software-switched forwarding
• Maximum Supported Frame Size: Jumbo frames up to 9216 bytes, baby giant frames up to 1600 bytes for legacy Metro Ethernet deployments
• Aggregation Capacity: Supports EtherChannel / PAgP / IEEE 802.3ad LACP link aggregation across line card ports, maximum 8 ports per logical EtherChannel bundle, cross-line-card EtherChannel supported
• MTBF: 280,365 operating hours under standard indoor environmental conditions
• Max Power Consumption of Line Card (excluding PoE load): 92 Watts maximum rated power draw
• Total Maximum PoE Power Budget Support: Dependent on Catalyst 4500E chassis high-wattage AC power supply configuration, supports simultaneous 15.4W IEEE 802.3af power delivery to all 48 ports when paired with sufficient power supplies.

PoE Power Delivery Specifications

• Supported Power Standards:
  1. IEEE 802.3af PoE: Up to 15.4W power output per RJ45 port (no native PoE+/30W support, unlike WS-X4648-RJ45V+E)
  2. Cisco proprietary pre-standard inline PoE for older Cisco powered devices
• Power Management Features: Per-port PoE enable/disable, PoE priority scheduling, power budget threshold SNMP alerting, automatic power shutdown for over-current/short-circuit port faults, real-time PoE power consumption monitoring and logging via CLI/SNMP.

Front Panel Physical Port & Indicator Layout

1. Gigabit Copper Ports (48 × RJ45 10/100/1000BASE-T PoE Ports)
   • Port speed auto-negotiation: 10Mbps / 100Mbps / 1000Mbps full-duplex, half-duplex fallback support
   • PoE powered device classification auto-detection: Automatically identifies 802.3af and Cisco pre-standard powered devices
   • Per-port bi-color status LEDs: Green = link up/active traffic, Amber = PoE fault, port disabled, link down, power overload condition
2. Module System Status Indicators
   • Global module health LED: Solid green = operational normal, solid red = critical hardware fault, flashing amber = boot/diagnostic mode
   • Hot-swap ejector levers with integrated locking tabs for safe module insertion/removal without chassis power shutdown
3. No Integrated Console or Management Ports – all management interfaces reside on the chassis supervisor engine module.

Physical, Environmental & Power Specifications

Physical Dimensions & Weight

• Form Factor: Single-slot hot-swappable line card for Catalyst 4500E 19-inch rack chassis
• Overall Dimensions (H × W × D): 3.0 cm × 36.2 cm × 27.3 cm (1.2 in × 14.25 in × 10.75 in)
• Bare Line Card Net Weight: ~1.05 kg

Environmental Operating Specifications

• Operating Ambient Temperature Range: 0°C to 40°C (32°F to 104°F) standard data center/wiring closet environment
• Storage & Transport Temperature Range: -40°C to 75°C (-40°F to 167°F)
• Operating Relative Humidity: 10% to 90% non-condensing humidity for 24/7 continuous chassis operation
• Operating Altitude: -60 meters up to 3000 meters above sea level
• Acoustic Noise: No onboard cooling fans; all thermal dissipation via passive heatsinks; chassis cooling fans handle overall system thermal load
• Carrier-Grade Compliance: NEBS Level 3 (GR-1089-CORE, GR-63-CORE), ETSI ETS-300386-2, EN 50121-4
• Safety Certifications: UL 1950, EN 60950, CSA-C22.2 No.950, IEC 60950-1.

3. Supported Layer 2 / Layer 3 Protocol & Feature Set

Layer 2 Switching Features

• IEEE 802.1Q tagged VLAN trunking, maximum 4094 active concurrent VLANs
• Spanning Tree Protocol suite: IEEE 802.1D STP, 802.1w Rapid STP (RSTP), 802.1s Multiple STP (MSTP); UplinkFast, BackboneFast, root guard, BPDU guard
• Link Aggregation: IEEE 802.3ad LACP, Cisco PAgP, cross-line-card EtherChannel support
• Multicast Optimization: IGMP v1/v2/v3 hardware snooping, Cisco Group Multicast Protocol (GMP) server functionality
• Link Fault Detection: Unidirectional Link Detection (UDLD) and aggressive UDLD modes
• Security Layer 2 Features: Port security, MAC address learning limits, static secure MAC binding, private VLANs with promiscuous trunk support, Q-in-Q VLAN stacking pass-through
• Energy Efficiency: IEEE 802.3az Energy Efficient Ethernet (EEE), automatic port power-down for idle link states
• Traffic Suppression: Broadcast, multicast, unknown unicast storm control (software rate-limiting)
• Misc Layer 2: Cisco Discovery Protocol (CDP), Layer 2 protocol tunneling (L2PT), CoS mutation for trunk ports.

Layer 3 Routing Features

• IPv4 Hardware Forwarding: Static routing, default static routes, EIGRP stub routing support, IP unnumbered SVI interfaces, SVI autostate exclude
• IPv6 Forwarding: Software-switched IPv6 packet forwarding (no dedicated IPv6 hardware ASIC acceleration)
• Access Control Lists: Hardware-based Port ACLs (PACLs), VLAN ACLs (VACLs), Router ACLs (RACLs) with zero performance overhead
• WCCP Version 2 Layer 2 redirect support for web cache offloading.

QoS Traffic Management Features

• Hardware Per-Port QoS Architecture: 4 independent egress hardware queues per RJ45 port
• Traffic Classification Mechanisms: Layer 2 CoS marking, Layer 3 DSCP / IP Precedence classification, full Layer 3/Layer 4 ACL header matching for granular traffic identification
• Policing & Shaping: 512 independent ingress policer instances, 512 independent egress policer instances; aggregate and per-flow policing modes, egress traffic shaping and bandwidth sharing
• Congestion Avoidance: Dynamic Buffer Limiting (DBL) to prevent egress buffer overflow and random packet loss
• Scheduling Algorithms: Strict priority queuing for real-time voice/video traffic, weighted round-robin (WRR) shared queue scheduling for data traffic
• Unified Communications QoS: Auto-QoS CLI template for simplified VoIP and TelePresence deployment, per-port/per-VLAN CoS/DSCP marking and mutation.

Enterprise Security Features

• IEEE 802.1X port-based Network Access Control (NAC) compatible (NAC processing handled by supervisor engine)
• DHCP Snooping with DHCP Option 82 insertion to block rogue DHCP server attacks
• ARP Inspection (DAI) for Layer 2 ARP spoofing attack prevention
• Encrypted management traffic support: AES encryption for SSH v2, TLS 1.1/1.2 for HTTPS web administration (security functions managed via supervisor IOS/IOS XE firmware)

High Availability Redundancy Features

• Hot-swappable line card design: Insert, remove, or replace the module without powering down the entire Catalyst 4500E chassis
• Stateful Switchover (SSO) and Non-Stop Forwarding (NSF) compatibility: When paired with dual redundant E-series supervisors, line card Layer 2 MAC tables and forwarding state are synchronized for subsecond failover with zero data-plane traffic outage.

4. Network Security & QoS Compliance Standards

1. Dual-stack IPv4 / IPv6 network protocol support; DHCP dynamic IP addressing or static IP configuration managed via chassis supervisor engine
2. Enterprise Network Access Security Controls: IEEE 802.1X EAP-TLS/EAP-PEAP wired authentication, multi-level local administrator password access control, role-based access control (RBAC) for web-based device management portal
3. Remote Administration Security Protocols: Encrypted SSH v2 secure shell CLI remote access, HTTPS TLS 1.1 / TLS 1.2 encrypted web management portal, XML/SOAP encrypted remote API interfaces for third-party network monitoring systems
4. Digital Identity Certificate Support: Manufacturer-Installed Certificates (MIC), Locally Significant Certificates (LSC), and X.509 DER/Base64 digital identity certificates for secure TLS authentication to TACACS+/RADIUS AAA servers
5. QoS Traffic Prioritization Compliance: IEEE 802.1Q VLAN tagging for logical segmentation of voice/media traffic and enterprise data traffic; IEEE 802.1p Layer 2 CoS marking to prioritize real-time VoIP and TelePresence video conference streams above standard office data packets, eliminating media latency and packet loss artifacts.

5. Unified Communications & Network Automation Feature Set

Core Enterprise Unified Communications & Meeting QoS Feature Set

1. Supported Unified Communications Deployment Scenarios:
   • Enterprise campus access layer Gigabit PoE copper aggregation for Cisco CUCM IP phone endpoints
   • Low-power enterprise Wi-Fi access point PoE power and data aggregation
   • Converged fixed IP surveillance camera and desktop endpoint edge aggregation
2. Complete Voice & Video Call QoS Control Operations:
   • Auto-QoS template automatic CoS/DSCP marking for VoIP media packets on PoE access ports
   • Strict priority egress queue scheduling to guarantee low-latency transport for TelePresence video conference traffic
   • Per-port ingress policing to limit rogue voice/video stream bandwidth consumption and protect mission-critical media traffic
   • OBTP (One Button To Push) calendar-scheduled meeting dynamic QoS policy activation; line card automatically prioritizes video conference traffic during pre-booked enterprise TelePresence meetings
3. Directory & Network Log Management Capabilities:
   • LDAP corporate directory lookup compatibility integrated with Cisco Unified Communications Manager (CUCM) and Cisco TelePresence Management Suite (TMS)
   • Persistent local switch logging storage on supervisor onboard flash memory; remote syslog server export for centralized enterprise network audit tracking
4. Supplementary Unified Communications Features: Integrated visual voicemail indicator support for IP phone endpoints, single number reach mobility feature support, ad-hoc point-to-point video conference traffic prioritization; URI dialing support for SIP video endpoints, RFC 4733 DTMF tone transmission for analog PSTN gateway integration; NTP network time synchronization for accurate meeting log timestamps, DNS service discovery, automatic gatekeeper discovery for legacy H.323 TelePresence endpoint interoperability.

Intelligent Network Workflow Automation Functions

1. OBTP Scheduled Meeting QoS Sync: When enterprise video conferences are scheduled via Microsoft Outlook/Google Calendar and launched from Cisco TelePresence endpoints connected to the Catalyst 4500E switch, the WS-X4648-RJ45V-E line card automatically applies high-priority QoS policies to all PoE copper access ports carrying conference media traffic without manual administrator configuration
2. Automatic System Hardware Fault Monitoring: Continuous real-time monitoring of line card temperature, port link status, PoE power draw, transceiver fault conditions; automated SNMP trap alert generation sent to enterprise network monitoring servers for hardware failure pre-alerting
3. Multi-Platform Meeting Interoperability: Native certified support for Cisco Webex Meetings traffic QoS prioritization, all third-party standards-compliant SIP/H.323 video conferencing endpoints without requiring auxiliary external AV switching hardware or third-party media bridge equipment
4. Multi-Mode Device Control Interfaces: Full Catalyst 4500E chassis and line card function control via three independent user interface methods:
   • Local RJ-45 console CLI (primary local administrator control method for all switch configuration and troubleshooting functions, located on chassis supervisor engine)
   • Remote HTTPS encrypted web administration portal for off-site enterprise IT administrator full chassis configuration and real-time port/route status monitoring
   • Bidirectional SNMP v2c / v3 MIB control integration for third-party enterprise network monitoring automation systems (SolarWinds, PRTG, Zabbix)
5. Third-Party Enterprise Network Monitoring Automation Integration: Supports SNMP trap notification linkage with third-party network monitoring platforms, standardized MIB object libraries for chassis resource utilization tracking, fully customizable automation macros for scheduled switch configuration backup, IOS/IOS XE image upgrade scheduling, and routine port status audit workflows
6. Digital Signage Kiosk Standby Mode QoS: Configurable automatic QoS policy adjustment for connected digital signage kiosk endpoints during off-hours non-meeting periods, lowering signage traffic priority to reserve uplink fiber bandwidth for critical enterprise voice and video conference traffic.

6. Supported Enterprise Compatibility Platforms

1. On-Premises Unified Communications Architecture: Cisco Unified Communications Manager (CUCM) version 8.x, 9.x, 10.x stable official software releases with dedicated Catalyst 4500E access layer switch voice VLAN and QoS compatibility configuration templates, integrated with Cisco Unified Presence (Jabber IM/presence synchronization) and Cisco TelePresence Management Suite (TMS) for enterprise-wide IP phone and video conference endpoint full-lifecycle management
2. Remote Access & Cloud Hybrid Architecture: Cisco TelePresence Expressway-C / Expressway-E cross-firewall traversal gateways for secure off-site remote TelePresence endpoint registration across corporate network firewalls via Gigabit Ethernet wired LAN infrastructure; native support for Cisco WebEx cloud meeting platform and Cisco TelePresence Management Suite (TMS) centralized on-premises device management portal
3. Third-Party Interoperability Compliance: Fully standards-compliant SIP RFC signaling protocol, H.323 and H.460 firewall traversal communication protocols, compatible with all industry-standard third-party video conferencing platforms, IP PBX telephone systems and multi-vendor TelePresence endpoint hardware from competing collaboration vendors, as well as all third-party enterprise network monitoring and SNMP management platforms.

7. Core Deployment Advantages of Cisco WS-X4648-RJ45V-E Line Card

1. Compact single-slot hot-swappable line card form factor optimized for Catalyst 4500E modular chassis campus access layer wiring closet deployments; 48 independent IEEE 802.3af PoE Gigabit RJ45 copper ports deliver cost-effective low-power PoE power+data aggregation, supporting legacy Cisco IP phones, single-radio Wi-Fi APs and fixed HD surveillance cameras without external power injectors
2. Native enterprise-grade 802.1X NAC security policy enforcement meets strict enterprise, government, healthcare and financial regulated industry network access compliance standards, enabling deployment within classified corporate campus and branch office network environments without external dedicated standalone security gateway hardware
3. 24 Gbps shared 2:1 oversubscribed per-slot switching fabric delivers cost-efficient Gigabit access layer forwarding for converged voice, wireless, video and data enterprise traffic while maintaining low chassis power consumption (92W max for line card itself, independent of PoE load)
4. Built-in SSO/NSF redundant high availability compatibility eliminates requirement for complex external routing protocol failover architecture for campus access layer networks, reducing enterprise unified communications hardware capital expenditure for headquarters and regional branch office deployments
5. Native IEEE 802.3af PoE 15.4W per-port power delivery fully supports legacy low-power enterprise endpoints, while backward compatibility with Cisco pre-standard PoE protects existing IP phone infrastructure investments; flexible PoE power budgeting and priority scheduling prevent chassis power overload faults during peak load conditions
6. Passive heatsink cooling design delivers zero audible operational noise for the line card module itself; all cooling load is handled by the main Catalyst 4500E chassis power supply fans, making WS-X4648-RJ45V-E ideal for quiet office wiring closet and executive campus network closet environments where noisy active-cooled line card modules create disruptive background distractions
7. Full backward compatibility with all legacy Catalyst 4500E series chassis and E-series supervisor engines, fully interoperable with existing enterprise CUCM/VCS/TMS on-premises unified communications infrastructure, enabling cost-effective legacy PoE access line card hardware replacement without full corporate campus access layer switch chassis refresh investment
8. Centralized mass Gigabit Ethernet wired LAN device fleet management via CUCM, TMS or VCS simplifies bulk IOS/IOS XE firmware batch upgrades, batch standardized enterprise security/QoS policy template deployment, real-time distributed headquarters/branch office Catalyst 4500E chassis hardware health monitoring and remote IT administrator troubleshooting, drastically reducing daily enterprise IT administration workload for large-scale distributed global corporate headquarters and regional branch office network fleets.

8. Supplementary Product Specification Notes

SKU / Model Naming Recap

• WS-X4648-RJ45V-E: Cisco Catalyst 4500E Series 48-port 2:1 oversubscribed Gigabit Ethernet RJ45 IEEE 802.3af PoE hot-swappable modular line card, 24 Gbps shared per-slot switching capacity, native IEEE 802.3af 15.4W PoE (no PoE+ support) + backward Cisco pre-standard PoE compatibility, IEEE 802.3az Energy Efficient Ethernet, compatible exclusively with Catalyst 4500E chassis and E-series supervisor engines, universal 100–240V AC chassis power input compatible, K9 secure IOS/IOS XE firmware compliant with AES encrypted management traffic and full enterprise NAC security policy support for regulated industry campus access layer low-power PoE endpoint deployments.
• K9 Compliance Note: All factory WS-X4648-RJ45V-E IOS/IOS XE firmware releases implement H.235v3 AES 128-bit encrypted remote CLI, web portal and SNMP management traffic, meeting Cisco K9 secure network hardware classification standards required for government, military, healthcare, and financial regulated enterprise campus and branch office network deployments.
• NR Variant Note: No separate RF-restricted NR cellular radio variant exists for WS-X4648-RJ45V-E; the line card contains no integrated cellular mobile radio signal generation or transmission modules, all network connectivity is delivered exclusively via RJ45 copper PoE ports only.

Regulatory Compliance Certifications

Fully compliant with global international industry certification standards including EU Low-Voltage Directive 2014/35/EU (IEC/EN 60950-1), EMC Electromagnetic Compatibility Directive 2004/108/EC, UL 60950-1 safety certification, CAN/CSA-C22.2 No. 60950-1, FCC CFR 47 Part 15 Class B electromagnetic emissions certification for office IT networking equipment, NEBS Level 3 carrier-grade compliance, ETSI ETS-300386-2, EN 50121-4, and global RoHS5 hazardous substance restriction compliance approval.

Factory Hardware Warranty Terms

Standard 1-year limited hardware warranty coverage for brand-new factory-sealed complete WS-X4648-RJ45V-E line card modules purchased through official Cisco authorized global distribution channel partners. Critical lifecycle limitation note: The product EoS/EoSS status restricts active hardware replacement warranty service eligibility for all WS-X4648-RJ45V-E units purchased after Cisco’s official End-of-Sale cutoff date; all formal Cisco technical TAC engineering hardware repair support services terminated permanently at the published End-of-Support date.

UNSPSC Classification Code

43222612 (Hot-swappable modular enterprise LAN switch line card for Catalyst 4500E chassis, 48-port 2:1 oversubscribed Gigabit RJ45 IEEE 802.3af PoE access layer interfaces, 24Gbps shared per-slot switching fabric, 15.4W PoE power delivery, hardware QoS and enterprise NAC security feature support, AES encrypted network management traffic, compatible with E-series Catalyst 4500 modular rack-mount campus access layer chassis switches).