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Mobile Wireless: How Your Cellular Phone Surfs the Internet: FAQ from Live Webcast



Mobile wireless is on the forefront of technology. Today, you can stream movies, attend a class, or share presentations — all on your mobile device. More importantly, since you are mobile, you are not constrained to a location. Instead, you can blend work and play into your life.


During the webcast, you will receive an overview of Long Term Evolution (LTE) and a detailed explanation of the subscriber call flow with Cisco expert Deepak Michael. He will explain common mobile wireless terminology; the fundamentals of LTE; and how a Packet Data Protocol (PDP) context is created, from the end user powering a mobile device to surfing the web. Deepak also explains how a subscriber is created on the Evolved Packet Core (EPC) System Architecture Evolution (SAE) gateway (GW) by outlining the various control and data plane messages. A primary takeaway includes looking at configuration commands entered on a Cisco Aggregate Services Router (ASR) 5500, which enables operators to utilize the SAE GW functionality.

Deepak Michael is a network consulting engineer and technical lead in the AT&T Mobility team at Cisco. He is an expert in Evolved Packet Core (EPC) and wireless mobility technologies, which includes Serving GPRS Support Node (SGSN), Gateway GPRS Support Node (GGSN), and EPC. Deepak has 14 years of experience working with domestic and international customers. He holds a degree in Business Administration from University of Phoenix and certifications in Cisco Certified Network Professional (CCNP), Cisco Certified Internetwork Professional (CCIP®), as well as mobile specialist certifications.

Webcast related links:

Q. What packet is used for GSM?

A. There are multiple aspects used for Global System for Mobile Communications (GSM). A link is provided at the end of the slide deck with the different releases for different interfaces, such as the call flow forGeneral Packet Radio Service (GPRS) Tunneling Protocol (GTP) Control Plane (GTPC), GTU, GSX, and how LTE has different interfaces. The slide deck references all information related to releases. Releases 9 and 10 always have Third-Generation Partnership Project (3GPP).

Q. What packet is used for CDMA?

A. Code Division Multiple Access (CDMA) uses 3GPP2. It is a different spec.

Q. What is a Bearer?

A. It is a device which communicates with devices and provides information such as Quality of Service (QoS), IP address, precedence, and so on. It comprises of many things and provides device communication.

Q. What is the Port for GTPC?

A. GTPC uses Port 21 and Port 23.

Q. What is TID?

A. General packet radio service (GPRS) Tunneling Protocol (GTP) version 2 uses LTE. It is a different version of GTPC, and it is for point-to-point connection for user plain for single mobile.

Q. What is NSAPI?

A. Network Service Access Point Identifier (NSAPI) is a mobile device communication with the network, which is a network service application point within the network.

Q. What is the difference between primary and secondary PDP?

A. Primary Packet Data Protocol (PDP) is like a default bearer, and a dedicated bearer is like a primary and secondary PDP. For example, IPv4 and IPv6 PDP.

Q. What is APN?

A. Access Point Name (APN) is company or service-specific. It is based on your mobile device, and it can have an APN, which maps it to a service. So when we power-on our mobile device, the APN tells the network how your device should be handled, on what gateway to be, or what mobile pools are to be used for corporate customers. For example, there are specific APNs, which are mapped with their own VPN (Virtual Private Networking) Routing and Forwarding (VRF), IP pools, or VPN tunnels.

Q. In regard to security solutions, what is the continued evolvement because more software-based technologies are being compromised?

A. For security evolvement, it is a dual approach that the actual mode devices will have security algorithm based within in them. You can also use your end-to-end security. In the case of VPN tunnel usage, you can use your laptop with firewall permitting and other options if you want total security. For your end-to-end flow, you can have commercial APN built within Aggregation Services Routers (ASR) or gateway routers, and you can further segment through the content so that you isolate your network from other networks.

Q. What entry-level Cisco courses covers this and towards which certifications? Is this under Wireless?

A. You can visit the Cisco Learning Network (CLN) site on that provides all the information about certification.

Q. How do PCRF and subscriber QoS levels fit into the LTE architecture?

A. They come in initially during the session establishment for a user. The policies are sent over from the Policy and Charging Rules Function (PCRF) to the Policy and Charging Enforcement Function (PCEF), which works hand-in-hand with the Packet Data Network Gateway (PGW). During the course of the session, updates are sent over by PCRF to the PCEF over Gx interface.

Q. What are the benefits of LTE?

A. LTE is for high-speed data. For providers, it is makes the networks smaller, what mobile devices are used from ad end user prospective. We can have streaming audio/video, voice conferencing, and higher bandwidth. LTE is opening doors for customer who want to use high-speed data on their device, with the use of hot spots for high data and low latency.

Q. For software upgrade, the ASR 5500 is a hitless function during the upgrade so is there no impact when the subscriber has a PDP Context Active?

A. Yes, ASR 5500 software upgrade will be an in-service upgrade.

Q. As mobility continues to grow in organizations (BYOD - bring your own device), how can/does security integrate with the continued need for robust solutions without compromising data confidentiality?

A. When enterprises subscribe, they actually buy space on the gateway GPRS support node (GGSN). Wireless providers can have their own APN build on GGSN and all the mobile devices attached to the network using this APN like Cisco and went to the gateway. This is okay, because they are coming to the network with the APN like Cisco, which has its own IP pool for them. It also has its own Multiprotocol Label Switching (MPLS) network or IPsec tunnel. Subscribers can buy APN or usage of ASR that facilitates these solutions.

Q. If you configure APN QoS profile in your Packet Switch (PS) Core, will this not work until PCRF knows and has QoS parameters configured?

A. PS QoS is not configured on the GWs. It comes from the PCRF over the Gx interface. PCEF and GWs only apply what they receive.

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