{"id":105563,"date":"2014-07-29T23:01:44","date_gmt":"2014-07-29T21:01:44","guid":{"rendered":"http:\/\/mybroadband.co.za\/news\/?p=105563"},"modified":"2014-07-29T23:02:41","modified_gmt":"2014-07-29T21:02:41","slug":"hidden-activity-when-you-use-your-smartphone","status":"publish","type":"post","link":"https:\/\/mybroadband.co.za\/news\/cellular\/105563-hidden-activity-when-you-use-your-smartphone.html","title":{"rendered":"Hidden activity when you use your smartphone"},"content":{"rendered":"

When you switch on your smartphone and request a website, you do not have to wait for long before it displays on the screen.<\/p>\n

What happens behind the scenes in a few seconds – from the time you switch on your smartphone to the time the website is fully loaded – is surprisingly complicated.<\/p>\n

Your mobile phone has to attach to the network, get authenticated, the network must make sure you have the funds for a required transaction, and your requests must be executed.<\/p>\n

There are six basic steps in the full process:<\/p>\n

    \n
  1. Attaching to the Network<\/li>\n
  2. Data session initiated<\/li>\n
  3. Authentication (Part 2)<\/li>\n
  4. Billing<\/li>\n
  5. Data delivered<\/li>\n
  6. Ending a data session<\/li>\n<\/ol>\n

    Each of these steps are explained in more detail, below.<\/p>\n

    \"Mobile<\/a>

    Mobile phone connection<\/p><\/div>\n

    Step 1: Attaching to the Network (pre-data session)<\/h3>\n
      \n
    1. Turn device on: When a subscriber switches on their device a location update takes place and a request is sent to the SGSN (Servicing GPRS Support Node) – (The SGSN works in conjunction with the Gateway GPRS Support Node (GGSN) to maintain a mobile user’s connection to the Internet and packet-based mobile applications. The SGSN handles data tunneling from devices to the GGSN and vice versa. The node also maintains the wireless session if the user is on the move.)<\/li>\n
    2. Authentication (1): At this point the SGSN is not aware of whether the subscriber is a valid subscriber and whether they have data activated. To find this out the SGSN checks with the HLR (Home Location Register). (The HLR is a central database that contains details of each subscriber that is authorised to use the network. The HLRs store details of every SIM card issued. Each SIM has a unique identifier called an IMSI which is the primary key to each the HLR.)<\/li>\n
    3. GPRS update location accept: When the subscriber is verified the HLR then forwards an update message to the SGSN as well as the customer\u2019s profile.<\/li>\n
    4. Attach Accept: The SGSN then sends an attachment message to the subscriber and this completes the authentication process to attach to the network.<\/li>\n<\/ol>\n

      Step 2: Data session initiated<\/h3>\n
        \n
      1. Create PDP context request: When the subscriber types in www.google.co.za (or any other address) and presses the connect button on their device, a Create PDP context message is sent from the subscriber to the SGSN. (A PDP context provides access to an external packet-switching network through the network.)<\/li>\n
      2. Where to from here: The SGSN does not know which GGSN to forward the request to and so it sends a DNS (Domain Name Server) query with the APN, eg internet.mnc001.mcc655.gprs to the DNS.<\/li>\n
      3. DNS response: The DNS responds with a GGSN IP address. Once the SGSN has this IP address it will forward the Create PDP context request to the correct GGSN (Gateway GPRS Support Node).<\/li>\n<\/ol>\n

        (The GGSN converts incoming data traffic from subscribers (via the SGSN) and forwards it to the relevant network, and vice versa. The GGSN is also linked into hosted services (such as voice and video) and to the billing, policy control, and user verification elements of the core network.)<\/p>\n

        Step 3: Authentication part 2<\/h3>\n
          \n
        1. GGSN authentication (2): At this point the GGSN is not aware of the subscriber and therefore needs to re-authenticate. To do this a request is sent to the ACG (authentication server) which queries the subscriber\u2019s details with the CUR (Central user repository).<\/li>\n
        2. CUR verification: The CUR verifies the subscriber and sends a response with the subscribers profile as well as a billing plan ID.<\/li>\n
        3. Initial balance check: The ACG then sends an initial balance check to verify whether the subscriber has enough money to browse the internet.<\/li>\n
        4. Accept: If the subscriber does have money the ACG will send an accept request to the GGSN.<\/li>\n
        5. Create PDP context Accept: A create PDP context accept message is now sent from the GGSN to the SGSN with a PUSH back IP address that will be assigned to the subscriber. This effectively means a \u201ctunnel\u201d has been created between the subscriber and the network.<\/li>\n
        6. Get URL request: The URL e.g. www.google.co.za is now sent from the subscriber\u2019s device directly to the GGSN.<\/li>\n<\/ol>\n

          Step 4: Billing<\/h3>\n
            \n
          1. Authorisation request: The GGSN then verifies that the URL is off-net and a request for a certain quota of money is sent to the C@O.<\/li>\n
          2. Authorisation response: C@O assigns the quota and forwards it to the GGSN.<\/li>\n
          3. Get URL request: GGSN will now forward this request to the CDN (content delivery network), which then routes this request to the internet.<\/li>\n<\/ol>\n

            (A content delivery network or content distribution network (CDN) is a large distributed system of servers deployed in multiple data centers across the Internet. The goal of a CDN is to serve content to end-users with high availability and high performance. CDNs serve a large fraction of the Internet content today, including web objects (text, graphics and scripts), downloadable objects (media files, software, and documents), applications (e-commerce, portals), live streaming media, on-demand streaming media, and social networks.)<\/p>\n

            Step 5: Data delivered<\/h3>\n
              \n
            1. Data delivered: The web page will then be pushed to the subscriber from the Internet. As this happens the GGSN is counting the number of bytes passing through for that session and deducts the quota accordingly.<\/li>\n
            2. Re-authorisation request: When the quota reaches a certain threshold the GGSN will then request more quota for that session from C@O.<\/li>\n
            3. Re-authorisation response: C@O will assign quota accordingly.<\/li>\n<\/ol>\n

              Step 6: Ending a data session<\/h3>\n
                \n
              1. Delete PDP context request: When the user completes the session and disconnects, a delete PDP context is initiated from the subscriber to the GGSN via the SGSN.<\/li>\n
              2. Service Stop: A service stop message is sent to C@O to stop the session and terminate and clear the connection from the GGSN and SGSN.<\/li>\n<\/ol>\n

                Thanks to Vodacom for helping with the\u00a0information.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

                What happens in a few seconds when you switch on your smartphone and request a website may surprise you<\/p>\n","protected":false},"author":23,"featured_media":89607,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_sma_x_autopost_status":"idle","_sma_x_autopost_error":"","_sma_x_post_id":"","_sma_facebook_post_id":"","_sma_instagram_post_id":"","_sma_threads_post_id":"","_sma_x_attempts":0,"footnotes":""},"categories":[14],"tags":[25805,35,41],"class_list":["post-105563","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cellular","tag-cellular-network","tag-headline","tag-vodacom"],"_links":{"self":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/105563"}],"collection":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/users\/23"}],"replies":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/comments?post=105563"}],"version-history":[{"count":2,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/105563\/revisions"}],"predecessor-version":[{"id":105575,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/posts\/105563\/revisions\/105575"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/media\/89607"}],"wp:attachment":[{"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/media?parent=105563"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/categories?post=105563"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mybroadband.co.za\/news\/wp-json\/wp\/v2\/tags?post=105563"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}