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GPRSposter 28 5/9/00 9:59 Page 1 C M Y CM MY CY CMY K World of GPRS GPRS Call Setup MS BSS SGSN Old SGSN GGSN EIR MSC/VLR HLR Old MSC/VLR Combined GPRS / IMSI Attach Procedure Attach Request Identification Request Identity Request Identification Response PSTN Identity Response Signaling Plane SGSN - HLR Signaling Plane SGSN MSC/VLR Routing Areas and Location Areas SM - SC Voice Switched Network SGSN Update Location Cancel Location Gr E Gs IMEI Check MAP TCAP SCCP MTP3 MTP2 L1 MAP TCAP SCCP MTP3 MTP2 L1 GMSC E BSSAP+ SCCP MTP3 MTP2 L1 BSSAP+ SCCP MTP3 MTP2 L1 Authentication SGSN E Cancel Location Ack HLR MSC/VLR Insert Subscriber Data LA Signaling Plane SGSN - SMS-GMSC and SGSN - SMS-IWMSC LA MS LA F MSC/VLR A Abis G Gs Signaling Plane MS - SGSN MAC GSM GSM RF Intra SS7 Network MAP TCAP SCCP MTP3 MTP2 L1 SMS-MSC SGSN Gd C PCU BSC Base Station Subsystem BTSM RLC BTSM BSSGP Network Service GMM/SM LLC BSSGP Network
Service L1 bis L1 bis L1 bis L1 bis Abis BSC Gc Gc H Gf F Location Update Request H Gb Gs PC Gc SGSN GGSN Gn IP / X.25 SNDCP LLC RLC MAC MAC BTSM RLC BTSM GSM RF GSM RF L1 bis L1 bis Um BTS Abis Attach Complete Reallocation Procedure HLR P-TMSI Reallocation Command Relay BSSGP Network Service SNDCP LLC BSSGP Network Service GTP UDP/TCP IP L2 IP/X.25 GTP UDP/TCP IP L2 L1 bis L1 bis L1 L1 BSS Gb Gn SGSN GGSN P-TMSI Reallocation Complete Intra PLMN IP Backbone Firewall Gn Border GGSN GSM Entities GGSN Signaling Plane GSN - GSN Inter PLMN IP Backbone GTP UDP IP L2 L1 GSN Gn GTP GTP UDP IP L2 L1 GGSN GTP UDP IP L2 L1 Activate PDP Context - MS Initiated Interworking Gp GPRS Entities Signaling Plane GGSN - HLR Using GTP and MAP Gi - IP Gi L e g e n d TMSI Reallocation Complete Gc IP Network Relay Gn UDP IP MAP TCAP SCCP MTP3 MAP TCAP SCCP MTP3 L2 L1 MTP2 L1 MTP2 L1 GSN Gc Activate PDP Context Request Security
Functions Create PDP Context Request Activate PDP Context Accept Create PDP Context Response HLR Gi - x.25 Activate PDP Context - GSN Initiated Firewall PDP PDU GSN Send Routing Info for GPRS X.25 Network PDU Notification Request Request PDP Context Activation MTP1 MTP2 MTP3 RLC Q.703 Q.704 GSM 04.60 Name Description Name Identifier Message Transfer Part - Level 1 Used as the physical layer for SS7 signaling. APN Access Point Name Message Transfer Part - Level 2 Supports Mobile Application Part (MAP) and BSSAP+ in circuit switched PLMNs - Message Transfer Part - Level 3 Radio Link Control BSSGP Virtual Connection Identifier Flow identifier between BSS and SGSN, at least 1 per GPRS cell. Supports Mobile Application Part (MAP) and BSSAP+ in circuit switched CI Cell Identifier Identifies a cell, as defined by GSM 03.03 PLMNs - for layer 3. DLCI Data Link Connection Identifier Identifier of the frame, corresponding to a Frame Relay PVC. Provides a
logical link control over the radio interface. GSN Address GPRS Support Node Address Unique IP address, not accessible to the public network. GSN Number GPRS Support Node Number Unique identifier for accessing SS7 entities; if a GGSN interfaces the HLR directly (and not Radio Link Protocol Provides non-transparent data services of GSM circuit switched network. NS-Network GSM 08.16 Network Service Manages the convergence sub-layer that operates between BSSGP and the LLC GSM 04.64 Base Station System GPRS Protocol Logical Link Control IMEI International Mobile Equipment Identifier Unique identifier for each GSM and GPRS handset. Frame Relay services. IMSI International Mobile Subscriber Identity Unique identifier for each GSM and GPRS MS, as defined by GSM 03.03 Routing and quality of service (QoS) information for the BSS. LAI Location Area Identifier Defined by operator, spanning one or more cells. MS-ISDN Mobile Subscriber ISDN ISDN access number. N-SAPI
Network Layer Service Access Point Identifier Identifies the PDP SAP for network routing. NSEI Network Service Entity Identifier Network entity address, with end-to-end significance. NS-VCI Network Services - Virtual Connection Identifier End-to-end logical identifier between BSS and SGSN. NS-VLI Network Services - Virtual Link Identifier Physical (local) link identifier between BSS and SGSN. Data link layer protocol assuring reliable transfer of user data. Q.921 Link Access Protocol - Channel D BSTM GSM 08.58 Base Station Controller to Base Transceiver Station Interfaces the base station controller with the base transceiver station. GSM 04.08 GPRS Mobility Management through an SGSN), it must have a GSN Number. Frame Relay Q.922 core by mapping BSSGPs service requests to the appropriate LAPD GMM/SM Balanced layer 2 protocol. Handles mobility issues such as roaming, authentication and selection of encryption algorithms, and maintains PDP context. SNDCP GSM
04.65 Sub-Network Dependent Convergence Protocol Maps IP or X.25 to the LLC; also provides functions such as compression, segmentation and multiplexing of network-layer messages to a single virtual connection. GTP SCCP GSM 09.60 Q.713, ANSI TI112 GPRS Tunnel Protocol Signaling Connection Control Part Identification of external networks; within the GPRS backbone, used to identify corresponding GGSN. BVCI GSM 04.22 GSM 08.18 Definition for layer 2. RLP BSSGP PDU Notification Response GSM AND GPRS IDENTIFIERS GSM AND GPRS PROTOCOLS Standards Send Routing Info for GPRS Ack PDP Context Activation Procedure GPRS Reference Protocol Cancel Location Ack Attach Accept MAP TCAP SCCP MTP3 MTP2 L1 MAP TCAP SCCP MTP3 MTP2 L1 EIR Relay Insert Subscriber Data HLR AuC SGSN Application Cancel Location Update Location Ack Location Update Accept Signaling Plane GGSN - HLR Gr Update Location Insert Subscriber Data Ack EIR Gr Gf Gd Transmission Plane MS Update
Location Ack Gf SGSN Gb BTS MAP TCAP SCCP MTP3 MTP2 L1 D Relay Um MS MAP TCAP SCCP MTP3 MTP2 L1 MAP TCAP SCCP MTP3 MTP2 L1 SMS - GMSC Gd BTS GMM/SM LLC RLC MAC Insert Subscriber Data Ack D LA Relay Signaling Plane SGSN - EIR C Tunnels protocol data units through TCP/UDP over IP. Supports Mobile Application Part (MAP) and BSSAP+ in circuit PDP Address Packet Data Protocol Address Network layer address (e.g IPv4, IPv6, X25) P-TMSI Packet TMSI Temporary identity for each attached GPRS MS. RAI Routing Area Identifier Defined by operator, spanning one or more LA. 2G 2.5G 3G Application MAP INAP TDMA(IS-136B) 14.4 bps IS-136+ 64 Kbps UWC-136 48.6 Kbps-52 Mbps IS41/MAP VLR AUC EIR HLR Presentation IS-136HS 43.2 Kbps Session EDGE 40 Kbps (384 Kbps with GPRS) Transport From UDP WSP ISUP TUP TCAP WTP DUP BSSMAP DTAP SS To IP Tunnel Identifier Used by GTP between GSNs to identify a PDP context consisting of an IMSI and an NSAPI. TLLI
Temporary Logical Link Identifier Used to identify logical links between the SGSN and MS. Temporary Mobile Subscriber Identity 1G GPRS Protocol Stack WAE TID TMSI The Evolutionary Path to 3G HSCSD 57.6 Kbps WTLS EGPRS 384 Kbps CM/CC GTP BSSAP MM To X.25 WDP Temporary identity for each attached GSM MS. From UDP SMS UDP B-ISUP SCCP RR switched PLMNs. BSSAP+ GSM 09.18 BSSAP with data functionality GPRS 160 Kbps Enables paging for voice connections from MSC via SGSN, optimizing paging for mobile subscribers, location and routing updates, as well as mobile station alerting. BSSAP GSM 08.06 BSS Application Part Supports signaling between MSC and BSS for call setup, and control channels. DTAP GSM 04.08, 0808, 0806 Direct Transfer Application Sub-Part Transfers call control messages and mobility management messages between IS - 634A the MSC and the MS. GSM AND GPRS INTERFACES Description Entity Name Description A Interface between BSC and MSC AuC
Border Gateway Authentication Center Gateways between PLMNs and external inter-PLMN Base Station Controller Base Station Sub-system Base Transceiver Station Equipment Identity Register Gateway GSN Gateway MSC GPRS Support Node Home Location Register Location Area Mobile Station Mobile Switching Center Network Switching Sub-system Packet Control Unit Public Land Mobile Network Public Switched Telephone Network Routing Area Serving GSN Registered user of a mobile station Transcoding Rate and Adaptation Unit Transmission/Reception Unit Visitor Location Register GSM 04.08 Mobility Management Manages location updating, handovers, and registration procedures. Abis Interface between BTS and BSC RR GSM 04.08 Radio Resource Management Controls setup, maintenance, and termination of radio channels. Air (Uu) Interface between MS and BTS CM/CC GSM 04.08 Connection Management Handles general call control and supplementary services. B Interface between MSC and VLR Supplementary
Services Supports supplementary services such as call forwarding. C Interface between MSC and HLR SMS GSM 04.11, 0412 Short Message Service Transfer a short text message between an MS and a Short Message Entity D Interface between VLR and HLR MAP GSM 09.02 Mobile Application Part Supports signaling between SGSN/GGSN and HLR/ AuC/ EIR. E Interface between MSCs BSSMAP GSM 08.08 BSS Management Application Part Supports the procedures between MSC and BSS. F Interface between MSC and EIR ISUP Q.763, ANSI TI112 ISDN User Part Set up, manages and releases voice/data calls. G Interface between VLRs H Interface between the HLR and AuC Gb Interface between BSC and SGSN Gc Interface between GGSN and HLR Gd Interface between SGSN and SMS-Gateway MSC DUP Q.741, X61 Data User Part Call control, facility registration and cancellation for common signaling. TCAP Q.773, ANSI TI1149 Transactions Capabilities Application Part Supports functions and procedures for
an application running on one network node to invoke execution of an application of another node and exchange results / database information. B-ISUP Q.2763 Broadband ISDN User Part Adds broadband digital circuits and data transmission using both Gf Interface between SGSN and EIR Gi Interface between PLMN and external packet data networks physical circuit and virtual circuit support to ISUP. IS-41/MAP EIA/TIA-41 Mobile Application Part for IS-41 Networks (public or private) Supports authentication, equipment identification and roaming in Gn Interface between SGSN and GGSN on same PLMN IS-41 networks. Gp Interface between SGSN and GGSN on different PLMN INAP Intelligent Network Application Part Service-independent capabilities in SS7. Gr Interface between SGSN and HLR O&M Operation & Maintenance Vendor-specific protocols for operating and maintaining the BTS and BSC. Gs Interface between SGSN and VLR BSC BSS BTS EIR GGSN GMSC GSN HLR LA MS MSC NSS PCU
PLMN PSTN RA SGSN Subscriber TRAU TRX VLR Other Bearers IP MTP3 UMTS 384 Kbps-2 Mbps GSM 14.4 Kbps GCC BCC SNDCP GMM/SM NM SMS PDC 14.4 Kbps LLC AMPS/N-AMPS 9.6 Kbps Data Link CDMAone(IS-95) 14.4 Kbps IS-95B 64 - 115Kbps CDMA 2000 144 Kbps BSSGP RLC MTP2 NS MAC BTSM Frame Relay LAPDm LAPD PDH (E1) GSM RF HDR 300 - 600 Kbps (downstream) Physical Product brand names may be trademarks of their respective owners and are mentioned for reference only. Information subject to change without notice. RADCOM makes no warranty of any kind, expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. RADCOM is not liable for errors contained herein. MTP1 PDH (E1 Abis) Protocol information and updates: RADCOM home page: www.protocolscom www.protocolsco www.radcom-inccom RA - PGPRS. Revision A Interface MM SS GSM AND GPRS ENTITIES Network International Headquarters: RADCOM Ltd., 12
Hanechoshet Street, Tel-Aviv 69710, Israel Tel: +972-3-6455055, Fax: +972-3-6474681, E-mail: info@radcomcoil US Office: RADCOM Equipment Inc, 575 Corporate Drive, Mahwah, NJ 07430, USA Tel: (201) 529-2020, Fax: (201) 529-0808,1-800-RADCOM-4 Composite
Service L1 bis L1 bis L1 bis L1 bis Abis BSC Gc Gc H Gf F Location Update Request H Gb Gs PC Gc SGSN GGSN Gn IP / X.25 SNDCP LLC RLC MAC MAC BTSM RLC BTSM GSM RF GSM RF L1 bis L1 bis Um BTS Abis Attach Complete Reallocation Procedure HLR P-TMSI Reallocation Command Relay BSSGP Network Service SNDCP LLC BSSGP Network Service GTP UDP/TCP IP L2 IP/X.25 GTP UDP/TCP IP L2 L1 bis L1 bis L1 L1 BSS Gb Gn SGSN GGSN P-TMSI Reallocation Complete Intra PLMN IP Backbone Firewall Gn Border GGSN GSM Entities GGSN Signaling Plane GSN - GSN Inter PLMN IP Backbone GTP UDP IP L2 L1 GSN Gn GTP GTP UDP IP L2 L1 GGSN GTP UDP IP L2 L1 Activate PDP Context - MS Initiated Interworking Gp GPRS Entities Signaling Plane GGSN - HLR Using GTP and MAP Gi - IP Gi L e g e n d TMSI Reallocation Complete Gc IP Network Relay Gn UDP IP MAP TCAP SCCP MTP3 MAP TCAP SCCP MTP3 L2 L1 MTP2 L1 MTP2 L1 GSN Gc Activate PDP Context Request Security
Functions Create PDP Context Request Activate PDP Context Accept Create PDP Context Response HLR Gi - x.25 Activate PDP Context - GSN Initiated Firewall PDP PDU GSN Send Routing Info for GPRS X.25 Network PDU Notification Request Request PDP Context Activation MTP1 MTP2 MTP3 RLC Q.703 Q.704 GSM 04.60 Name Description Name Identifier Message Transfer Part - Level 1 Used as the physical layer for SS7 signaling. APN Access Point Name Message Transfer Part - Level 2 Supports Mobile Application Part (MAP) and BSSAP+ in circuit switched PLMNs - Message Transfer Part - Level 3 Radio Link Control BSSGP Virtual Connection Identifier Flow identifier between BSS and SGSN, at least 1 per GPRS cell. Supports Mobile Application Part (MAP) and BSSAP+ in circuit switched CI Cell Identifier Identifies a cell, as defined by GSM 03.03 PLMNs - for layer 3. DLCI Data Link Connection Identifier Identifier of the frame, corresponding to a Frame Relay PVC. Provides a
logical link control over the radio interface. GSN Address GPRS Support Node Address Unique IP address, not accessible to the public network. GSN Number GPRS Support Node Number Unique identifier for accessing SS7 entities; if a GGSN interfaces the HLR directly (and not Radio Link Protocol Provides non-transparent data services of GSM circuit switched network. NS-Network GSM 08.16 Network Service Manages the convergence sub-layer that operates between BSSGP and the LLC GSM 04.64 Base Station System GPRS Protocol Logical Link Control IMEI International Mobile Equipment Identifier Unique identifier for each GSM and GPRS handset. Frame Relay services. IMSI International Mobile Subscriber Identity Unique identifier for each GSM and GPRS MS, as defined by GSM 03.03 Routing and quality of service (QoS) information for the BSS. LAI Location Area Identifier Defined by operator, spanning one or more cells. MS-ISDN Mobile Subscriber ISDN ISDN access number. N-SAPI
Network Layer Service Access Point Identifier Identifies the PDP SAP for network routing. NSEI Network Service Entity Identifier Network entity address, with end-to-end significance. NS-VCI Network Services - Virtual Connection Identifier End-to-end logical identifier between BSS and SGSN. NS-VLI Network Services - Virtual Link Identifier Physical (local) link identifier between BSS and SGSN. Data link layer protocol assuring reliable transfer of user data. Q.921 Link Access Protocol - Channel D BSTM GSM 08.58 Base Station Controller to Base Transceiver Station Interfaces the base station controller with the base transceiver station. GSM 04.08 GPRS Mobility Management through an SGSN), it must have a GSN Number. Frame Relay Q.922 core by mapping BSSGPs service requests to the appropriate LAPD GMM/SM Balanced layer 2 protocol. Handles mobility issues such as roaming, authentication and selection of encryption algorithms, and maintains PDP context. SNDCP GSM
04.65 Sub-Network Dependent Convergence Protocol Maps IP or X.25 to the LLC; also provides functions such as compression, segmentation and multiplexing of network-layer messages to a single virtual connection. GTP SCCP GSM 09.60 Q.713, ANSI TI112 GPRS Tunnel Protocol Signaling Connection Control Part Identification of external networks; within the GPRS backbone, used to identify corresponding GGSN. BVCI GSM 04.22 GSM 08.18 Definition for layer 2. RLP BSSGP PDU Notification Response GSM AND GPRS IDENTIFIERS GSM AND GPRS PROTOCOLS Standards Send Routing Info for GPRS Ack PDP Context Activation Procedure GPRS Reference Protocol Cancel Location Ack Attach Accept MAP TCAP SCCP MTP3 MTP2 L1 MAP TCAP SCCP MTP3 MTP2 L1 EIR Relay Insert Subscriber Data HLR AuC SGSN Application Cancel Location Update Location Ack Location Update Accept Signaling Plane GGSN - HLR Gr Update Location Insert Subscriber Data Ack EIR Gr Gf Gd Transmission Plane MS Update
Location Ack Gf SGSN Gb BTS MAP TCAP SCCP MTP3 MTP2 L1 D Relay Um MS MAP TCAP SCCP MTP3 MTP2 L1 MAP TCAP SCCP MTP3 MTP2 L1 SMS - GMSC Gd BTS GMM/SM LLC RLC MAC Insert Subscriber Data Ack D LA Relay Signaling Plane SGSN - EIR C Tunnels protocol data units through TCP/UDP over IP. Supports Mobile Application Part (MAP) and BSSAP+ in circuit PDP Address Packet Data Protocol Address Network layer address (e.g IPv4, IPv6, X25) P-TMSI Packet TMSI Temporary identity for each attached GPRS MS. RAI Routing Area Identifier Defined by operator, spanning one or more LA. 2G 2.5G 3G Application MAP INAP TDMA(IS-136B) 14.4 bps IS-136+ 64 Kbps UWC-136 48.6 Kbps-52 Mbps IS41/MAP VLR AUC EIR HLR Presentation IS-136HS 43.2 Kbps Session EDGE 40 Kbps (384 Kbps with GPRS) Transport From UDP WSP ISUP TUP TCAP WTP DUP BSSMAP DTAP SS To IP Tunnel Identifier Used by GTP between GSNs to identify a PDP context consisting of an IMSI and an NSAPI. TLLI
Temporary Logical Link Identifier Used to identify logical links between the SGSN and MS. Temporary Mobile Subscriber Identity 1G GPRS Protocol Stack WAE TID TMSI The Evolutionary Path to 3G HSCSD 57.6 Kbps WTLS EGPRS 384 Kbps CM/CC GTP BSSAP MM To X.25 WDP Temporary identity for each attached GSM MS. From UDP SMS UDP B-ISUP SCCP RR switched PLMNs. BSSAP+ GSM 09.18 BSSAP with data functionality GPRS 160 Kbps Enables paging for voice connections from MSC via SGSN, optimizing paging for mobile subscribers, location and routing updates, as well as mobile station alerting. BSSAP GSM 08.06 BSS Application Part Supports signaling between MSC and BSS for call setup, and control channels. DTAP GSM 04.08, 0808, 0806 Direct Transfer Application Sub-Part Transfers call control messages and mobility management messages between IS - 634A the MSC and the MS. GSM AND GPRS INTERFACES Description Entity Name Description A Interface between BSC and MSC AuC
Border Gateway Authentication Center Gateways between PLMNs and external inter-PLMN Base Station Controller Base Station Sub-system Base Transceiver Station Equipment Identity Register Gateway GSN Gateway MSC GPRS Support Node Home Location Register Location Area Mobile Station Mobile Switching Center Network Switching Sub-system Packet Control Unit Public Land Mobile Network Public Switched Telephone Network Routing Area Serving GSN Registered user of a mobile station Transcoding Rate and Adaptation Unit Transmission/Reception Unit Visitor Location Register GSM 04.08 Mobility Management Manages location updating, handovers, and registration procedures. Abis Interface between BTS and BSC RR GSM 04.08 Radio Resource Management Controls setup, maintenance, and termination of radio channels. Air (Uu) Interface between MS and BTS CM/CC GSM 04.08 Connection Management Handles general call control and supplementary services. B Interface between MSC and VLR Supplementary
Services Supports supplementary services such as call forwarding. C Interface between MSC and HLR SMS GSM 04.11, 0412 Short Message Service Transfer a short text message between an MS and a Short Message Entity D Interface between VLR and HLR MAP GSM 09.02 Mobile Application Part Supports signaling between SGSN/GGSN and HLR/ AuC/ EIR. E Interface between MSCs BSSMAP GSM 08.08 BSS Management Application Part Supports the procedures between MSC and BSS. F Interface between MSC and EIR ISUP Q.763, ANSI TI112 ISDN User Part Set up, manages and releases voice/data calls. G Interface between VLRs H Interface between the HLR and AuC Gb Interface between BSC and SGSN Gc Interface between GGSN and HLR Gd Interface between SGSN and SMS-Gateway MSC DUP Q.741, X61 Data User Part Call control, facility registration and cancellation for common signaling. TCAP Q.773, ANSI TI1149 Transactions Capabilities Application Part Supports functions and procedures for
an application running on one network node to invoke execution of an application of another node and exchange results / database information. B-ISUP Q.2763 Broadband ISDN User Part Adds broadband digital circuits and data transmission using both Gf Interface between SGSN and EIR Gi Interface between PLMN and external packet data networks physical circuit and virtual circuit support to ISUP. IS-41/MAP EIA/TIA-41 Mobile Application Part for IS-41 Networks (public or private) Supports authentication, equipment identification and roaming in Gn Interface between SGSN and GGSN on same PLMN IS-41 networks. Gp Interface between SGSN and GGSN on different PLMN INAP Intelligent Network Application Part Service-independent capabilities in SS7. Gr Interface between SGSN and HLR O&M Operation & Maintenance Vendor-specific protocols for operating and maintaining the BTS and BSC. Gs Interface between SGSN and VLR BSC BSS BTS EIR GGSN GMSC GSN HLR LA MS MSC NSS PCU
PLMN PSTN RA SGSN Subscriber TRAU TRX VLR Other Bearers IP MTP3 UMTS 384 Kbps-2 Mbps GSM 14.4 Kbps GCC BCC SNDCP GMM/SM NM SMS PDC 14.4 Kbps LLC AMPS/N-AMPS 9.6 Kbps Data Link CDMAone(IS-95) 14.4 Kbps IS-95B 64 - 115Kbps CDMA 2000 144 Kbps BSSGP RLC MTP2 NS MAC BTSM Frame Relay LAPDm LAPD PDH (E1) GSM RF HDR 300 - 600 Kbps (downstream) Physical Product brand names may be trademarks of their respective owners and are mentioned for reference only. Information subject to change without notice. RADCOM makes no warranty of any kind, expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. RADCOM is not liable for errors contained herein. MTP1 PDH (E1 Abis) Protocol information and updates: RADCOM home page: www.protocolscom www.protocolsco www.radcom-inccom RA - PGPRS. Revision A Interface MM SS GSM AND GPRS ENTITIES Network International Headquarters: RADCOM Ltd., 12
Hanechoshet Street, Tel-Aviv 69710, Israel Tel: +972-3-6455055, Fax: +972-3-6474681, E-mail: info@radcomcoil US Office: RADCOM Equipment Inc, 575 Corporate Drive, Mahwah, NJ 07430, USA Tel: (201) 529-2020, Fax: (201) 529-0808,1-800-RADCOM-4 Composite
When reading, most of us just let a story wash over us, getting lost in the world of the book rather than paying attention to the individual elements of the plot or writing. However, in English class, our teachers ask us to look at the mechanics of the writing.
