RPL protocol

Low power and Lossy Networks (LLNs) are a class of network in which both the routers and their interconnect are constrained. RPL routing protocol, which provides a mechanism whereby multipoint-to-point traffic from devices inside the LLN towards a central control point, as well as point-to-multipoint traffic from the central control point to the devices inside the LLN, is supported. Support for point-to-point traffic is also available.

RPL protocol is easy to adopt to network changes and allows to have multiple logical topologies over a single physical topology. Moreover, it provides a loop avoidance and detection mechanism, and it takes into account both link and node properties when choosing paths. However, it assumes other mechanism can be used to provide security.

Nowadays, RPL routing protocol is used in 6LoWPAN and generic LLN networks. There were some successful implementations in TinyOS, and with the deployment of IPv6 it is expected to have more implementations and successful results.



A Passive Optical Network (PON) is a point-to-multipoint, fiber to the premises network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve multiple premises, typically 16-128.

A PON consists of an Optical Line Terminal (OLT) at the service provider’s central office and a number of Optical Network Units (ONUs) near end users. It reduces the amount of fiber and central office equipment required compared to point to point architectures. A passive optical network is a form of fiber-optic access network. GPON (Gigabit Passive Optical Network) deals with optical communications a Gigabit level providing more symetric traffic and efficient resources utilization.


The 3GPP Release 8 standard specifies the 4G Evolved Packet System (EPS), which includes the E-UTRAN (access network also known as LTE) and EPC (core network also known as SAE).


System Architecture Evolution (SAE) is the evolution of the GPRS Core Network. It is a simplified architecture where the intelligence is in the access network instead of the core network. It is an all-IP Network and supports higher throughput and lower latency radio access networks, including E-UTRA (LTE and LTE-Advanced air interface), 3GPP legacy systems (GERAN or UTRAN) and non-3GPP systems (WiMAX or cdma2000).


The EPS, also known as LTE, is designed to provide high data rates and low latency using a flat, all-IP network architecture. The EPS is standardized to provide all services including mobile broadband data, high-quality voice, and multimedia services.

Downlink peak data rates provided by LTE up to 100Mb/s and 50Mb/s in the uplink. It operates in both TDD and FDD modes and it has a scalable bandwidth up to 20MHz, covering 1.4, 3, 5, 10, 15 and 20MHz. The usage of OFDMA (SC-FDMA in the uplink) and MIMO technic increase spectral efficiency over 3 times.


HSPA+, or Evolved High-Speed Packet Access, is a technical standard for wireless, broadband telecommunication. HSPA+ enhances the widely used UMTS based 3G networks with higher speeds for the end user, which is comparable to the newer LTE networks.

HSPA+ was first defined in the technical standard 3GPP release 7 and expanded further in later releases. HSPA consist on HSDPA (Downlink) and HUSPA (Uplink) which are completely different systems (the only thing they have in common is the HARQ mechanism).

The usage of MIMO technics and 16/64QAM modulation in HSDPA provide higher data rates (14.4Mbps). HSPA+ increases the network capacity and the user data rates because of the better spectral efficiency. Moreover, it reuses UMTS architecture in order to minimize the capital expenditure of the operator, but base stations (NodeB) have more intelligence with RNC functions. The flattened all-IP architecture, where the stations connect to the network via IP, allows a faster and cheaper network.

In Spain, Movistar, Vodafone and Yoigo has commercially launched HSPA+ with speeds up to 42Mb/s in major cities.

Femtocells technology

With the explosion of the Internet connected devices, such as smartphones or tablets, the demand of higher data rates in wireless networks is increasing day by day. Consumers are increasingly sensitive to coverage for both voice and data, especially at home and in the office. Operators need to meet this demand quickly and at a reduced cost-per-bit, which is the main motivation of the femtocell technology

What is a femtocell?

A femtocell, also called home base station, is a low-power access point which is basically used to provide coverage and capacity in home and office environments. The femtocell is a small device connected to the service provider via broadband network (ADSL or cable) and supports simultaneous voice conversations and data services.

When the mobile phone is under the coverage of the femtocell, it switches over from the macrocell to the femtocell automatically. Then, the user has the same services but the connection comes from ADSL.


Despite there are different standards and technologies, all broadly conform to an architecture with three major elements:

  • femtocell acces point: connects to the mobile operator network via broadband network.
  • femtocell gateway: aggregates the traffic from different femtocells.
  • femtocell management system & security: manages different home base stations.


For a mobile operator, the attractions of a femtocell are improvements such as:

  • Better coverage and capacity because of the short distance between the transmitter (femtocell access point) and the receiver (mobile phone).
  • Improved macrocell reliability: traffic originating indoors can be absorbed into femtocell networks and the macrocell can redirect its resources.
  • Cost benefits: reduced operating and capital expenditure costs for operators.

Moreover, the femtocell provides to the user:

  • Better quality voice and high-speed data services, such as video streaming.
  • Security mechanism and protocols.
  • Prolong handset battery live because of the lower transmit power.

Deployment of femtocells

Several organizations are working to standardize femtocells technology: 3GPP, Broadband Forum, Femto Forum and Next Generation Mobile Network. The initial priority for standardization efforts was focused on 3G technologies, but nowadays the data rates are still lower than WiFi and that is why the deployment is lower than the operators commitment.

However, with LTE and 4G systems, which are designed to integrate femtocells in their architecture providing higher data rates, QoS and security (better than WiFi), femtocells are going to change the landscape of mobile technology and networking business in the coming years.

Deployment of IPv6

The pool of available IPv4 adresses is depleted because of Internet demographics, the expansion of Internet connected devices (laptops, smartphones, tablets), the always-on connection devices (ADSL/cable routers) and the inefficient address use. This problem has been a concern since 80s, when Internet started to growth dramatically, so some technologies have been designed to help to slow the exhastion such as classful networks, CIDR methods, and NAT. However, the accepted and standard solution is to use IPv6, which has many more adresses available.

IPv6 is the protocol currently used to direct almost all Internet traffic. IPv6 provides a substantially larger IP address space than IPv6 and has new characteristics:

  • IPsec mandatory to provide encryption and authentication.
  • Simplified processing in routers due to fixed header, checksum removed, no fragmetnation and TTL.
  • Mobility
  • Jumbograms through higher lenght limit than IPv4 (64kB to 4GB).
  • End-to-end connectivity

Nowadays, migration to IPv6 is in progress, but completion is expected to take considerable time. However, the sooner we implement IPv6, the better profits in ICT we will have: IPv6 is a must!

Solutions for Inter-Domain Routing Problem

Nowadays Internet has scalability problems: Routing Tables (RTs) are growing too fast.   Therefore better implementation of some routing techniques is needed, such as multihoming and traffic engineering.

Two representative solutions for the routing scalability problem are NNC and LISP.

Clean slate: NNC

NNC is a clean slate solution which defines a new routing paradigm: routing on content name instead of on content address. NNC improves delivery efficiency and solves the problems such as content availability, security, content location dependence, where vs what, named hosts vs named data and host-to-host vs many-to-many:

  • The communications are built on named data with no notion of the hosts.
  • The content node model have two types of packets: interest and data.
  • Transport operates on top of unreliable packet delivery services, has a flow control and the CNN can take advantage of multiple interfaces.
  • Intra-Domain Routing works with link state IGP, customizes link-state announcements and a CNN content advertiser can reach some of the content matching a prefix.

Evolutionary: LISP

The Locator Identifier Separation Protocol minimizes required changes to Internet. It doesn’t require hardware and software changes to endsystems (hosts) and is incrementally deployable. The principles of LISP are:

  • IP addresses have two complementary roles: identifier role and locator role. LISP defines a router-based solution where current IP addresses are separated in two different spaces: EndPoint Identifies (EID),  to identify end hosts, and Routing Locators (RLC), to attach to routers.
  • A mapping mechanism allows to map an EndPoint Identifier onto the routing Locators of the site routers.
  • Routers encapsulate the packets received from hosts before sending them towards the destination RLOC.
  • LISP site can control incoming traffic with Weight and Priority.

A few requirements are needed to implement LISP, specially in network equipment. Architectural changes are divided into:

  • Data-Plane: hosts and majority of routers are unaffected
  • Control-Plane: no changes within stub and core networks but the introduction of a Mapping System is required.
  • Tunnel Routers (TR): the introduction of these routers at border between edge and core.