WO2013043094A1

WO2013043094A1 - Caching in a telecommunication network

Info

Publication number: WO2013043094A1
Application number: PCT/SE2011/051141
Authority: WO
Inventors: Jari Vikberg; Lars Westberg
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2011-09-23
Filing date: 2011-09-23
Publication date: 2013-03-28
Anticipated expiration: 2014-03-23
Also published as: US20140359048A1; EP2759115A1; EP2759115A4

Abstract

A net-work node (1) of a telecommunication network (6) controls a play-out of cached content to a user equipment (2a, 2b). The network node retrieves an address contained in a response from the core network (5) to a request associated with the user equipment. If the network node detects that the address is associated with a defined server, e.g. a credit refill server or an advertisement server, the play-out of cached content to the user equipment is disabled. The play-out is activated again when a response to an additional request contains an address that is associated with another source than said defined server.

Description

Caching in a telecommunication network

TECHNICAL FIELD

The disclosure relates to a method in a network node of a telecommunication network for controlling a play-out of cached conten to a user equipmen . The disclosure also relates to a network node arranged to control a iay-out of cached content to a user equipment, The disclosure also relates to a caching unit, a radio base station, an eNodeB, a radio network controller, RNC, and a base station controller, BSC, comprising such a network node .

BACKGROUND

The 3GPP LTB (3rd Generation Partnership Project Long Term

Evolution) is a project for improving the UMTS (Universal Mobile Telecommunication System) -standard, in order to cope with future requirements in terms of improved services , such as higher data rates, improved efficiency, and lower costs. The radio access network of an LTS system is commonly referred to as an E-UTRAN (Evolved Universal Terrestrial. Radio Access Network) , and the iJ RAN is the radio access network according to the UM S .

In. an E-UTRAN, a user equipment, UE, is connected to a. radio base station commonly referred to as an eNodeB (evolved NodeB) , which is connected to a node in a. CN (Core Network) .

In a UTRAN, a user equipment is connected to a radio base station commonly referred to as a KiodeB, and the NodeB is conne ed to a network node of the UTRAN, typically an R!>IC {Radio Network Controller) , which is connected to the CM {Core network} ,

In a radio access network according to trie ^a generation, such as a radio access network of the GSM (Global System for Mobile communication) , the radio base station is referred to as a BIS {Base Transceiver Station) , which is connected to a core network via a etwork node of the radio access network, typically a Base Station Controller (BSC) .

Caching i a mobile (telecommunication} network involves that a copy of content, e.g. interne media content, is stored in a cache, server located within the telecoimsunications network, when the content is retrieved from e.g. a media server by an end- user. Thus, a copy of the content will be stored closer to the end-users, for example in the radio access network or in the core network, and will be available to other end-users. Thus, when another end-user (or the same end-user) is requesting the stored media content, it will be played-out directly from the cache server. Thereby, the request does not have to be forwarded to the core network, and the content does not have to be

downloaded from the media server again. Since a large percentage of the Internet traffic is repetitive, the caching of e.g.

Internet media content in the mobile network will reduce the sending of repeating content all the way from its origin to the end-us .

An advantage with caching in a mobile network is that it will decrease the transport cost, since a cached content in principle only has to be transferred once in the transmission links above the cache server. Another advantage is that it will improve the Quality of Experience for the end-user, due to a lower delay, since a content can. be retrieved faster from a cache server located in the telecommunication network, than from an original location, e.g. a media server.

Thus, caching in as mobile network may be used e.g. for media distribution towards a mobile end-user, wherein the media can be played-out to the mobile end-user directly from the cache server in the telecommunications network, instead of retrieved as downloadable media from a media server or from another user.

Figure 1 illustrates how media content, from a media server 7 is pushed to a cache server 3 of a mobile network 6, wherein mobile end-users 2a, 2b, are able to retrieve the content directly from the cache server, instead of having to dowiload it from the media server. The cache server 3 and the network node 1 for controlling the caching are typically located in the radio access network 4, but they could also be located in the core network 5. Obviously, other types of content than media content may also be cached.

Charging in a mobile network, e.g. online charging or offline charging, is performed by the different core networks ana the service network nodes. In online charging, the charging

information, e.g. regarding a subscriber credit, may affect a service to the end-user/subscriber in real time, and an. Online Charging System, OCS , typically performs real time credit control of a subscriber/end-use .

Figure 2 schema ically illustrates the functions of online charging, and the C.N Domain. 21, the Service Element 22 and the Sub-system 23. The CTF 28 (Charging Trigger Function) generates charging events based on the observation of network, resource usage. The CTF collects information pertaining to chargeable events and assembles this information into matching charging events . The CTF delays the actual resource usage until

permission has been granted by the OCS 25 (Online Charging System) , tracks the availability of resource usage permission during the network resource usage, and enforces a termination of the end user's network resource usage when permission by the CCS is not granted, or has expired, e.g. when the subscriber' of the end user is out of credit. The OCS .comprises an OCF 29 (Online Charging Function) , an RF 27 {Rating Function) for determining the value of the network resource usage, arid an AB.MF 26 {Account Balance Management Function. In on-line charging , the services provided to an end-user will be affected by the credit control performed by the OCS . However, if a copy of a media content requested by the end-user has been previously stored in a cache server, this cached content ma be played-out to a user equipment of the end-user, even though, the subscription has run out of credit.

Further, an end-user may be redirected to an adver isement server in order to receive an adver isement inserted e.g. in a media stream. However, if the media concent has been previously stored in a cache server, this content may be played-out to the .end-user anyway.

Thus, it is an overall problem that a. cached content,, e.g. .media content, is always played-out to the end-user.

SUMMARY

It is. an object of exemplary embodimen s described hereinafter to address at least some of the issues outlined, above, and this object and others are achieved by the methods and the

arrangements according to the appended independent claims, and by the embodiments according to the dependent claims.

A first aspect of the exemplary embodiments provides a method in a network node of a telecommunications network for controlling a play-out of cached content to a user equipmen . The method comprises the network node retrieving an address contained in a response to a request, wherein the reques is associated with the user equipment, and disabling a. play-out of cached content destined to the user equipraent, when detecting that the retrieved address is associated with, a server belonging- to a defined set of one or more servers. Said defined set of servers may be a set of credit refill servers or advertisements servers. The request may be sent from the user equipment, or,

alternatively, being initiated and sent by the network node.

The network node ma further^' retrieve an additional address, which is contained i a response to an addit onal request th t is associated with the user equipment, and activate a disabled play-out of cached content to the user equipment, when detecting that the retrieved additional address is associated with another source than said server belonging to the defined set of servers . The detecting may comprise the network, node comparing any of the one or mor retrieved addresses wi a stored listing of addresses associated with the defined set of servers, and the response containing the retrieved, address may be a Domain Name System-reply, or alternatively, the retrieved address may be a source address, e.g. an IP address.

The network, code may further update a listing of user equipment to which a play-out of cached content is disabled. A second aspect of exemplary embodiments provides a network node connec table to a telecojnmum cations network, wherein the network node is arranged to control a play-out of cached content to a. use equipment . The network node comprises a receiver

configured to receive a response to a .request, wherein the request is associated with the user equipment. The network node, also comprises a processing circuitry configured to retrieve an address contained in the response, and disable a play-out of cached content destined to the user equipment, when detecting that, the retrieved address is associated with, a server belonging to a defined set of one or more servers .

The processing circuitry may foe further configured to retrieve an additional address contained, in a response to an. additional request that is associated with the. user equipment, and to activate a disabled play-out of cached content to the user equipment, when detecting that the retrieved additional address is associated with another source than said server belonging to the defined set. of servers.

The network node may further comprise a memory for storing a listing of addresses associated with servers belonging to a defined set of servers.

The network node may comprise a xaemory for storinrj a listing of identities to user equipments to which a play-out of cached content is disabled, wherein the processing circuitry is configured to update the listing.

A third aspect of exempiary embodiments provides a caching^' unit comprising a cache server connected to a network node .according to exemplary embodiments . A fourth aspect of exemplary embodiments provides a radio base station, e.g. an eWodeB, connec able to a radio access network, wherein the radio base station comprises a network node

according to exemplary embodiments . A fifth aspect of exemplary embodiments provides an RN^'C thai:, is connectable to a UTRAiSf, or a BSC that is connectable to a GSM radio access network, wherein the RNC or the BSC comprises a network node according to exemplary embodiments . It is an advantage with, exemplary embodiments that a network node, e.g. in. a radio access network, can disable a play-out of cached content to an end-user in an uncomplicated way, e.g. when a subscription is out. of credit, or when the end-user is

redirected to an advertisement server. Another advantage is that the play-out can be easily activated again, e.g.. when, the subscription has been paid, or when the advertisement has been received by the end-user. BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will now be described in more detail, and with reference to the accompanying drawings , in which:

- Figure 1 schematically illustrates exemplary caching of

internet media content from a. media server;

- Figure 2 schem tically illustrates exemplary functions of

online charging in a 3GPP mobile network;

™ Figure 3 schematically shows an exemplary caching architecture comprising a radio access network, R¾3M, a core network, CM, and a media server., in order to ill s race a redirection of a reques

- The figures 4a, 4b and 4c are flow diagrams illustrating

methods in. a network node of disabling the play-out of. cached content to a user eguipnient belonging to an end-user,

according to exemplary embodiments;

- Figure 5 is a flow diagram of a method in a network node of activating a disabled play-out of cached content, according to exemplary embodimen s ;

- Figure 6a and 6h schematically illustrates an exemplary

network node, and its processing circuitry;

- Figure 7 schematically illustrates an exemplary caching unit, comprising a network node and cache server;

- Figure 8a schematically illustrates a radio base station

comprising an exemplary network node and a cache server, and figure 8b schematically illustrates an RNC or a BSC comprising an exemplary network node and a. cache server,

DETAILED DESCRI PTION

in the following description, di ferent exemplary embodiments are described, in more detail, with reference to accompanying drawings. For the purpose of explanation and not limitation, specific details are set. forth, such as particular scenarios and techniques in order to provide a thorough unders anding.

Moreover, it is apparent that the functions and means explained below may he implemented using software functioning in

conjunction with a programmed microprocessor or general purpose compi.it.er, and/or using an application specific integrated

circuit (ASIC) . Further, while the embodiments are primarily described in the form of methods and devices, the embodiments may also he implemented as a computer program product or in a system comprising a computer processor and a memory coupled to the processor, wherein the memory is encoded with one or more programs that may perform the. functions disclosed herein.

Furthermore, particular aspects of the embodiments are described in a non-limiting general context i relation, to an E~UTL¾K_f a UTRAH or a GSM RAN. However, it should be noted that the

embodiments may also be applied to other types of radio access networks. The user equipments described herein may include e.g. mobile telephones, pagers, headsets, laptop computers and other mobi1 e terminals . Figure 3 schematically illustrates an exemplary caching- architecture, wherein copies of content retrieved from a media server 7 can be stored in. a cache server 3 located in the radio access network, RAN. A network node 1 controls the caching,, i.e. the storing of content in the cache server and the play-out of. the cached, content froia the cache server to a user equipment , OE, 2. As described above, during online charging of a service provided to an end-user/su scriber associated with a HE, the subscriber may run out of credit. In such a case, a node in the core network.. e.g. an SASN 9 {Service Aware Support Mode) , ma redirect a content request to a credit refill server 8, instead, of providing the conten from the media server 7. This

redirection is preceded by the CIS detecting that a pre-paid subscription of the end-user has run out of credit. Thus, when the end-user of the UE 2 attempts to access an Internet home page from the media server 7, e.g. a home page belonging to a newspaper, and no copy of the home page has been previously stored in the cache server 3, the mobile CN will receive a ϋΞ HTTP request from the LIE to access the home page of the

newspaper. However , it the subscription has run out of credit:, the request is redirected to a so-called refill home page at the credit refill server 8 instead. This refill home page may be the only home page the end user is allowed to access until he/she has paid his/her subscription.

The above-described, situation, that a requested content is not found in a cache server, and the request is forwarded to he core n twork, is commonly referred to as a cache miss. The opposite situation,- i.e. that a requested content is found in a cache server, is commonly referred to as a cache hit.

Conventionally, if an Internet home page requested by the UE has been previously scored in the cache server 3, (i.e. a cache hit) , the UE will be able to retrieve the home page from the cache server, even though the subscription associated with the UE has run out of credit.

However, according to an embodiment disclosed herein, the network node 1 controlling the cache server 3 will disable the play-out of cached co.nt.ent. to this end user when his/her subscription has run out of credit, and activate the play-out when the subscription is paid. This is accomplished by the

network node inspecting downlink traffic to the UE and

discovering when a subscription associated with a UE is out of credit, e.g. by detecting that an address retrieved in a

response to a request associated wit the UE is associated with a credit refill server. Whe the network node has discovered that a UE is out of credit., it. disables a lay-out of cached content to this UE. In order to activate the play-out. again when the subscription is paid, the network, node may continue to inspect downlink traffic to the UE, in order to discover when the UE is not out of credit anymore. According to an exemplary embodiment , the network node discovers that a subscription is out of credit by performing packet inspection of downlink traffic to a UE, and determining if an address contained in a response from the core network to a request from the UE is associated with a specific server, e.g. with a credit refill server. If an address associated with such a server is detected, this indicates that the request will be, or has been, redirected to this specific server by the CN. I a first alternative embodiment, the network, node inspects the response to a D'S query from a UE, and in a second alternative embodiment, the netwarr. node inspects the source address, e.g. an IP address, of a response to a content request . In said first alternative embodiment, an answer to a DNS query from the UE for a host name, e.g. www.crm.coH!, has been overwritten by the core network , and an address, e.g. an IP address, to a defined server, e.g. a credit refill server, has been returned to the UE in DNS reply. Upon receiving the address, the UE will

establish a connection with, the defined credit refill server instead of with the CKK-server. In the second alternative embodiment, the IP layer has redirected a content, request from π the US to the defined server, e.g. a credit refill server, and the response contains the address of this server as a source address ,

Another exemplary embodiment is related to control of a pia.y-out of cached content, when an advertisement is inserted in a media stream. In suc a case, an end-user may be charged with a lower price, e.g. for accessing an Internet media content, since the operator is able to get a revenue from the advertisemen ,

According to this exemplary embodiment, a play-out of cached media content to an end -user should be disabled temporarily, when the end-user has been redirected to an advertisement server, and the play- out of cached content should, be activated again when the end-user receives traffic from a. different server than the advertisement server, Thus, i this embodiment, the play-out of cached conteri; to the US is disabled when the

etwork node detects tha a address retrieved in a response from the core network to a request from a US, or on behalf of a US, is associated with a server belonging to a defined set of advertisement servers. Fu the , the play-out ma be activated again when the network node: detects an address associated with a different server than. said, advertisement server in a response to a request.

According to a exemplary embodiment., the network, node 1 will retrieve an address, e.g. an IP address , contained in. a response to a request, and compare with a listing of stored addresses to different servers belonging to a defined set of one or more servers, e.g. credit refill servers or advert isement servers, to which the core network may redirect the OB, e.g. when a

subscription is out of credit, or for providing an advertis ment to the end-user. If the network node is able to find the

retrieved address in the listing of stored addresses, it will disable the play-out of cached content to the UE. According to a. further embodiment, the. network node will also store an identity of the UE, e.g. in a listing of iMSls (International Mobile Subscription Identities) associated with the UHs to which a play-out of cached content is disabled.

According to a further exemplary embodiment , in order to activate the disabled play-out of cached content again, e.g. when the subscription has been paid or when the adve tisemen has been received by the end-user, the network node will

retrieve an additional address contained in a. response froiB the core network to an additional request from said UE, and activate a disabled play-out of cached content to the UE ., when the retrieved address is associated with another source than a defined server. When the play-ouc is activated, the network node may also remove the UE from the listing of UEs .

The network node may investigate a response to a request

initiated and sent to the core network by the UE, e.g. a a cache miss, but the network node may also initiate so-called test traffic, e.g. at certain defined events , and initiate and send a request to the core network itself, on behalf of a US, and investigate the response. Such a test traffic request could e.g. be initiated and sent by the network node at a defined time interval after the last forwarding of a request to the core network.

Thus, according to a first exemplary embodimen , the network node investigates traffic created by the UE by retrieving an address contained in a response from the core network to a request initiated and sent by the UE. The retrieved address is inspected, and if an address associated with a server belonging to a defined set of servers is detected, the play-out of cached content is disabled by the network, node. When a play-out of cached content to a UE is active, the network node may investigate traffic created by the OE e.g. when a cache miss takes place, i.e. that a content requested by the UE is not found in the cache server, and the request is forwarded to the core network.

According to a second exemplary embodimen , the network node sends test traffic associated with a UE, by initiating and sending a request to the core network on behalf of the UE, and retrieving an address contained in a response to the request. This test, traffic, may be initiated at certain events or with certain time intervals, e.g. when a defined time period has passed since a content, reques was forwarded to the core

network.

Another exemplary embodiment combines the above-de cribed first and second exemplary embodiments, and comprises the network node retrieving an address in a response to a request sent from the UE and forwarded to the core network, e.g. at a cache miss, the network node also sending test, traffic at defined events,- by retrieving an address in a response to a. request initiated and. sent to the core network by the network node itself, the request, being associated with the UE .

The embodiment without test, traffic, comprising the network node only inspecting a response to a. recmest initiated by the UE, e.g. at a cache miss, is simple and requires no extra

signalling. However , to inspect test traffic initiated by the network node will enable a faster detection, e.g. of an out of credit.-situatio .

Another embodiment disclosed herein is specifically directed to activating a play-out of cached content to a user equipment. However, the activating according to this embodiment could be preceded by a disabled play-out according to an embodiment disclosed herein. According to the embodiment specifically directed to activating a play-out. of cached content to a user equipment, a network node 1 retrieves an address contained in a response to a request associated wi h the user equipment, and the address may .be contained in DNS reply, or be a source address of the response. If the network node detects that the retrieved address is associated w th another source than a specific server that belongs to a defined set of servers, the network node will activate a play-out of cached content to this user equipment-. The detecting may be performed by the network node comparing the retrieved address with a stored listing of address associated with a defined set of servers, e.g.

advertisement servers or credit refill servers. Figure 4a is a flow diagram schematically illustrating a method in a network node of a tel communications network of controlling the play-out of cached content to a user equi ment , according to an exemplary embodiment . In step 42, the netwox'k node retrieves an address in a response to a request associated with a user equipment, wherein the address may be. contained in a DNS-reply, or may be a source address of the response, if detecting, in step 43, that the retrieved address, e.g. an IP address, is associated with a server belonging to a defined set of servers, e.g. a credit refill server or an advertisemen server, the network node disables the play- out of the cached content to the user equipment, in ste 44. The detecting, in step 43, .may comprise comparing the retrieved address with a stored, listincf of addresses, Figure 4b is a flow diagram illustrating a first alternative embodiment of the method, illus ated in igure 4a, according to which the network node .retrieves an address in a response to a request, sent from the user equipment, in step 42a, e.g. at a cache miss, and the following steps in figure 4b, i.e., step 43 and step 44, correspond to the steps 43 and 44 illustrated in figure 4a.

Figure 4c is a flow diagram illustrating a second alternative embodiment of the method illustrated in figure 4a, according to which the network node retrieves an address in a response to a. request associated with a user equipment, in figure 42b, the request being ini iated, and sent by the network node. This step is preceded by the network node initiating and sending this reques on behalf of the user equipment, in step 41, e.g. at. a defined even . The following steps in figure. 4c, i.e. step 43 and step 44, correspond to the steps 43 and 44 illustrated in figure 4a and 4b. According to a further embodiment , the network node will update a listing of user equipment-identities to which a cache play-out is disabled, after disabling a cache play-out to a user

e u iptierit . Figure 5 is a flow diagram illustrating a method in a network node of a telecommunication network of activating a disabled play-out of cached content to a user equipmen , according to an exemplary embodimen . in step 52, the network node retrieves an address in a response to an. additional request, associated with a user equipment, wherein the address may be contained in a DNS- reply, or may be a source address of the response. If detecting, in step 53, that the retrieved address is associated with another source than a server belonging to a defined set of servers, e.g. a credit, refill server or an advertisement server, the network node activates a disabled play-out of the cached content to the user equipment, in step 54. However, if the retrieved address is an address of a server that belongs to the defined set of servers, then the play-out should not yet be activated. Instead, the network node will retrieve, in step 52, an additional address in a response to an additional request associated with the user equipmen , and perform an additional detecting step, 53, followed by a step 54 or a repeated step 52, depending on the outcome of the detecting step. The detecting in step 53 may comprise comparing the .retrieved address with a stored listing of addresses, e.g. IP-addresses.

According to a further embodiment:., the network node will update a listing of user equipment-identities to which a cache play-out is disabled, by removing the identity of the user equipment to the listing, after activating a disabled cache play-out to the user equipment.

Figure 6a illustrates schematically an exemplary network node 1, according to exemplary embodiments , the network node being connectable to a telecommunications network, e.g. to a radio access network or a core network,, and arranged to control a play-out of cached content to a user equipment. The network node is further connectable to a cache server (not illustrated in the figure.) The network node is provided with suitable

communication circuitry, comprising- a receiver 11, which is configured to receive a response to a request associated with a user equipment. The network node is further provided with appropriate processing circuitry 12 connected to the receiver 11, the. processing circuitry being configured to retrieve an address contained in the response, and disable a play-out of cached content to the user equipment, when detecting that the ■address is associated with a server belonging to a defined set of servers, e.g. of adverti ement servers or credit refill ervers .

The address, e.g. an IP address, may be retrieved from a response that is a DNS reply, or it may be she source address of the response. Said request may be initiated, and sent to the core network from the user equipment, e.g. at a cache miss, or may be initiated and sent, to the core network by the network node itself on behalf of the user equipmen , e.g. at a defined event.

According to an exemplary embodiment, the network node is further arranged to activate a disabled play-out of cached content to a user equipment . In this embodiment, the processing circuitry is configured to retrieve an additional address contained in a response to an additional request associated with the user equipmen , e.g. sent from the user equipment, or initiated and sent by the network node on behalf of the user equipment. The processing circuitry is configured to activate disabled play-out of cached content to the user equipment, when detecting that the retrieved address is associated w th another source than a server belonging to a defined set of servers, e.g. by comparing the retrieved address, typically an IP address, with a stored, listing of addre ses to the servers. The addresses may be stored in a memory located in the network node (not illustrated in figure 6a) .

According to a further" embodiment , the processing circuitry is also configured to update a. listing of identities of user equipments to wh ch a play- our. of cached, conten is disabled. Thus, v.hen the processing circuitry of the network node disables a cache play-out to a certain user equipment, the processing circuitry will also add the identity of this user equipment to said, listing. Similarly, when the processing circuitry activates a cache play-out to the user equipment, it will remove the identity of this user equipment from the listing. The listing is may be stored in a memory that is located in the network node (not illus rated in figure 5a) . Figure 6b schematically illustrates the processing circuitry 12, as illustrated in figure 6a. The processing circuitry comprises a CPU 121, which may be a single unit or a plurality of units. Furthermore, the processing circuitry comprises at least one computer program product 122, in the form of a non-volatile memory, e.g. an EEPROM (Electrically Erasable Programmable Read- Only Memory). , a flash memory or a disk drive. The computer program product 122 comprises a computer program 123 comprising computer program modules 123a, fo, c, which when run. on the network node 1 causes the CPU 121 to perform the steps performed in conjunction with figure 4a.

Hence, in the exemplary embodiment illustrated in figure 6b, the code means in the computer program 123 comprises a retrieving module 123a. a detecting module 123b, and a. disabling module 123c_; and the modules 123a, 123b and 123c may essentially perform the steps of the flow in figure 4a. However, one or more of the modules of the code means may in alternative embodiments be implemented partly as hardware circuits .

The network node 1 and the cache server 3 may be co-located to form a caching uni 70, or may alternatively be two separate devices that are connected to each other in order to perform the caching, Figure 7 illustrates schematically an exemplary caching unit 70, comprising an exemplary network node 1 connected to a cache server 3, the network node comprising a receiver 11 and a processing circuitry 12. The illustrated network node further comprises a sendex" 13 for sending a request on behalf of a user equipment, a memory 14a for storing a listing of servers

belonging to a defined set of servers, e.g. of advertisements servers or credit refill servers, and a memory 14b for storing a. listing of identi ies of the user equipment to which a play-out of cached content is disabled. The memories 14a or 14b may be located in the same storage device, or in separate storage devices, even though only one storage device is illustrated in figure 7.

It should be noted that both the above-described network node 1 and the caching unit 70 may be implemented by physical or

logical entities using software functioning in conjunction with a programmed microprocessor or general purpose computer, and/or using an application specific integrated circuit (ASIC) . It may further include suitable internal and external storage devices, a processor ox^" multiple processor cores, as well as appropriate communication interfaces, including hardware and software capable of performing the necessary modulating, coding,

filtering and the like, as well as demodulating and decoding of signals .

The network node 1, or a caching unit 70, may be located e.g. in a radio base station, for a radio access network, e.g. in an eModeB for the E-UTRAN , or in a radio access network-node

connected to the radio base s ation, e.g. in a radio network controller, RNC, for a UTRAN, or in a base station controller, BSC for a GSM RAN . However, since packet-switched traffic is normally encrypted in the GSM betwee the UE and a Serving GPRS (General Packet Radio Services) Support Node of the core network, an inspection of downlink traffic to a UE in a GSM RAN has to be adapted accordingly.

The network node, or a caching unit 70, may alternatively be located in a core network, CM, typically "below" the redirecting node,, e.g. a SASN 9, as illu trated in figure 3.

Figure 8a illustrates a radio base station 10, e.g. a eHodeB for an E-UTEAN, wherein the radio base station comprises a network node 1 connected to a cache server 3. The network node illustrated in this figure corresponds to the network node which is illustrated e.g. in figures 6a and 6b, arid which is further discussed above. The radio base station 10 may alternatively be provided with a caching unit 70, as illustrated in figure 7, nd comprising a network node 1 as illustrated in figure 6a and. 6b, and a cache serve 3 connected to the network node 1.

Figure 8b illustrates a radio access network-node 81, e.g. an. ENC tor a UTRA or a BSC for a GSM RAN, provided with a. network, node 1 connected to a cache server 3. Similarly as in figure 8a, the network node 1 corresponds to a network node as illus rated e.g. in figures 6a and 6.b. Also, the radio access network-node 81 raay alternatively be provided with a caching unit 70, as illustrated in figure 7, and comprising a network node 1 as illustrated in figure 6a and 6b, and a cache server 3 connected to th network node 1.

It raay be further noted that the above described embodiments are only given as examples and should not be lim ting to the present invention, since other solutions, uses, objectives, and

functions are apparent within the scope of the invention as claimed, in the accompanying patent claims .

Claims

1. A method in a network node < X) of a telecom unications network (6) for controlling a play-out of cached conten to a user equipment (2a, 2b), the method comprising:

- retrieving (42, 42a, 42b) an address contained in a response to a request, wherein the request is associated with the user equipmen , and

- disabling (44) a play --out of cached content destined to the user equipment, when detecting^' (43) that the retrieved address is associated, with a server belonging to a defined set of one or more servers .

2. h method according to cla m 1/ wherein the request is sent from the user equipment (2a, 2b) .

3. A method according to claim. 1, wherein the request is initiated and sent by the network node (1) .

4. A method according to any of the preceding claims, the method further comprising:

- retrieving (52) an additional address, the address contained in a response to an additional reques , wherein the additional request is associated with the user equipment ;

-- activating (54) a disabled play-out of cached content to the user equipment, when detecting (53) that the retrieved

additional address is associated with another source than said server belonging to the defined set of servers .

5. A method according to any of the preceding claim, wherein the detecting compr ses comparing any of the one or more retrieved, addresses w th a. stored listing of addresses associated with the defined set of servers .

6. A method according to any of the preceding claims, wherein the response is a Domain Name System-reply,

7 A method according to any of the claims 1 - 5, wherein the retrieved address is a source address.

8. A method according to any of the preceding claims , further comprising updating- a listing of user equipment to -whic a play-out of cached content, is disabled.

.9. A method according to any of the preceding claims, vmerein said defined set of servers is a set of credit refill servers.

1G, A method according to any of the clairas 1 - 8, wherein said defined set of servers is a set of advertisements

ser-vers .

11. A network node (1) connectable to a telecommunications network, the network node, arranged to control a play-out of cached content to a user equipmen {2a, 2b) , the network node comprisin ;

- a receiver (II) configured to:

sf receive a response to a -request, wherei the request is associated with the user equipme t, and

- a processing circuitry (12) configured to:

* retrieve an address contained in the response, and

« disable a play-out of cached content destined to the user equipment, when detecting that the retrieved

address is associated with a server belonging to a defined set of one or more servers .

12. A network node (1} according: to claim 11, wherein the request is sent from the user equipment .

13. A network node (1) according to claim 11 or 12, wherein the request is initiated and sent by the network node.

14. A network node according to any of the claims 11 - 13, wherein the processing circuitry (12) is further configured to :

- retrieve an addi ional address, the address contained in a response to an addi ional request, wherein the additional request is associated with the user equipment,, and

-- activate a disa.bl.ed play-out of cached content to the user equipment, when, detecting that the retrieved additional

address is associated with another source than said server belonging to the defined set of servers.

15. A network node according to any of the claim 11 -· 14, comprising a memory (14a.) for storing a listing of addresses associated with, servers belonging to a defined set of servers,

16. A network node according to claim .15, wherein the

detecting comprises comparing any of the. one or more retrieved addresses with, the listing of addresses .

17. A network node according to claim .16, wherein the

processing- cir-cuitry is configured to compare an address retrieved from a Domain Name System-reply with the stored listing of addresses.

18. A network node according to claim 16, wherein the

processing circuitry is configured to compare a retrieved source address of a response with the stored listing of addresses .

19. A network node according to any of the claims 11 - IS, comprising a memory (14b) for storing a listing of identities to user equipments to which a. play-out of cached content is disabled, wherein the processing circuitry {12} is configured to update t e list!ng .

20. A caching uni (70) comprising a cache server (3)

connected to a network node (1) according to any of the claims 11 - 19.

21. A radio base station (10} connectable to a radio access network (4) , the radio base station compx'isincr a network node (1) according to any of the claims 11 - 19.

22. An eNocleB (10) connectable to an E-UTRAN (45, the eMode comprising a network node (1) according to any of the claims 11 - 19,

23. A radio network controller (81) , RitfC, connectable to a

UTRAN (4), the RNC comprising a network node (1) according to any of the claims 11 - 19.

24. A base station controller (81), BSC, connectable to a GSM radio access network (4), the BSC comprising a network node (1) according to any of the claims 11 - 19.