{"product_id":"9781580536554","title":"SIP: Understanding the Session Initiation Protocol, Second Edition","description":"Introduces the session initiation protocol (SIP), which is a new signaling protocol developed to set up, modify, and tear down multimedia sessions over the Internet. Johnston, a former engineer at WorldCom, defines the types of clients and servers in a SIP network, and describes the function of request messages, response messages, and SIP headers. The second edition adds a chapter on SIP mobility and wireless multimedia communications. Annotation ©2004 Book News, Inc., Portland, OR  ","brand":"Artech House, Incorporated","offers":[{"title":"Default Title","offer_id":49787587625200,"sku":"9781580536554","price":99.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/shop-qa.barnesandnoble.com\/products\/9781580536554","provider":"Barnes \u0026 Noble (DEV)","version":"1.0","type":"link"}