GMPLS OUTSTANDING ISSUES

Some of the issues that need to be taken care of while using this technology are:
Security
Security
Traditional IP routing examines the contents of the header of a received packet to determine the next hop for it. While time-consuming, this step allows the establishment of firewalls, as the necessary information is available in the packet header—e.g., the source and the destination addresses that are globally unique. In contrast, GMPLS/MPLS labels are used to speed up the forwarding scheme and only have local significance—i.e., the label is only understood and used internally by the GMPLS device itself. As such, these labels cannot be used for access-control or network-security purposes. One way to establish security in a GMPLS network is to enforce access security during the connection set-up time, like other connection-oriented networks—e.g., X.25 or ATM.

Interworking

The success of GMPLS will partially depend on its ability to communicate with the many existing ATM or Frame Relay network infrastructures. Interworking with ATM and Frame Relay networks will allow transport of control and data plane information exchanged between two similar networks (e.g., two ATM networks) through a dissimilar network (e.g., GMPLS).
The implementation of interworking functions between these networks face these issues:
• Interworking in the control plane is very complicated as different suites of protocols are used in each network (e.g., routing, private network-to-network interface [PNNI] in ATM versus OSPF–TE in GMPLS networks).
• The maintenance of end-to-end service quality as usage data travels through dissimilar network types is essential.
• GMPLS switching can be packet-based, TDM–based, wavelength-based, waveband-based, or fiber-based. This creates quite a few combinations in the data-plane interworking context between GMPLS networks and ATM or frame-relay (FR) networks, which carry data in cells or frames, respectively.
• Several industry forums are currently addressing the specifics of interworking between these networks (e.g., the MPLS Forum, the ATM Forum, the Frame Relay Forum). Practical solutions must satisfy the carriers that manage both MPLS networks and legacy networks. These solutions remain undefined at this time.

Network Equilibrium

When a new resource is deleted or added in a GMPLS network, the set of control information that is exchanged is larger than that of a traditional IP network. GMPLS uses traffic-engineering models that include introducing a set of traffic parameters, associated with data links, performing constraints-based routing, LMPs, etc. While not tested, theoretically, an MPLS/GMPLS network would take a relatively longer time to achieve an equilibrium state than would a traditional IP network when the network is disrupted.

Network-Management Systems

The most important parameter in managing a traditional IP network—e.g., the Internet—is address reachability. In contrast, the GMPLS network-management system needs to keep track of several thousands (even millions) of LSPs for their operational status, routing paths, traffic engineering.