NLSR: Named Data Link State Routing Protocol

Named Data Networking (NDN) is a fundamental paradigm shift from the current Internet where, packets are forwarded by name instead of the destination IP address. By explicitly naming each packet and signing data, NDN enables some revolutionary features like data authenticity, multicast data delivery, and multipath forwarding with adaptive strategies. For NDN to work well over a network, it requires a routing protocol which will not only need to propagate name reachability in the network, but also compute ranked multipath forwarding entries for each name by ensuring the security of routing exchanges. Moreover, moving from a traditional, long studied, and well-understood IP based thinking process to name based routing makes designing an efficient routing protocol for NDN more challenging. This thesis presents Named-data Link State Routing (NLSR), which propagates name reachability and computes ranked multiple nexthops for forwarding. NLSR also takes advantage of inherent data authenticity features to provide simple yet robust security for routing exchanges.This thesis focuses on discussing four functional design goals of NLSR. First and foremost is designing a naming scheme for routers, routing updates, and routers\u27 cryptographic certificates. The second design goal is to make a rational choice between two available synchronization protocols for disseminating routing updates in NDN. The third goal is designing an efficient algorithm to produce multiple nexthops for each forwarding entry. The fourth and final goal is to produce a self-sufficient design for naming, distributing cryptographic certificates in the network, and deriving trust from those certificates for routing updates.The goal of this thesis is to design and evaluate a routing protocol, which will well serve the needs of NDN. NLSR moves from the conventional IP based routing to name based routing and from single path forwarding to multiple path forwarding. We have evaluated NLSR, and compared to IP link state routing protocol, it offers more efficient routing update propagation, inherent update authentication, and native support of multipath forwarding. NLSR provides a great learning experience to develop an application on top of NDN which requires meticulous consideration in namespace design, careful design of the trust model for data authentication, and most importantly, a mental adjustment to NDN\u27s design philosophy of using interest-data exchanges for routing messages. NLSR is the first distributed routing protocol in NDN for a single authoritative domain and the first step toward developing and extending protocols for inter-domain routing

Antibiotic residues in milk and eggs of commercial and local farms at Chittagong, Bangladesh

Aim: The study was conducted to detection and determination of concentration or level of antibiotic residues in milk and egg of local and commercial farms at Chittagong during December 2011 to June 2012. Materials and Methods: A total of 400 (200 milk and 200 egg) samples were collected from local and commercial dairy cows and local scavenging and commercial poultry farms, respectively. Microbial inhibition test and thin layer chromatography were used for screening and ultra-high performance liquid chromatography was used to estimate the concentrations of antibiotic residues in samples. Results: Tetracycline, amoxicillin, and ciprofloxacin residues were significantly (p ≤ 0.05) higher in commercial farms than local. The boiling insignificantly (p˃0.05) reduced residues level in milk and egg. The average concentrations of amoxicillin residue in local milk, commercial milk, local egg, and commercial egg were 9.84 μg/ml, 56.16 μg/ml, 10.46 μg/g and 48.82 μg/g, respectively, in raw samples and were reduced to 9.81 μg/ml, 55.54 μg/ml, 10.29 μg/g, and 48.38 μg/g, respectively, after boiling. Conclusions: Proper maintaining of the withdrawal period and development of active surveillance system are highly recommended for public health security

A survey of gastro-intestinal parasitic infection in domestic and wild birds in Chittagong and Greater Sylhet, Bangladesh

A survey of gastrointestinal parasitic infection as determined by faecal examination was conducted among domestic and wild birds in Bangladesh. Birds were sampled from households, wet markets and wetlands in Chittagong and Greater Sylhet districts during April 2012 to February 2013. Mist nets were used to catch resident wild and migratory birds. The overall prevalence of parasitic infection ranged among locations from 25 to 55% in indigenous domestic ducks (live bird samples. = 304), 20% in resident wild birds (environmental faecal samples. = 40) and 40% in migratory birds (live bird samples. = 35). The prevalence of parasitic infection was significantly higher in indigenous domestic ducks collected during summer (39%) than winter (22%) (p= 0.04). In domestic indigenous ducks and Muscovy ducks, both single and multiple types of parasitic infections were found. However, other domestic birds and wild birds often had a single type of parasitic infection. Ascaridia spp. with an average egg load of 50-900, was commonly detected in faecal samples of domestic and wild birds in this study. Other identified parasites were Capillaria spp. and Heterakis spp. both in domestic and wild birds. Improvement of biosecurity measures for household duck farms through educating and motivating household farmers could help mitigate the effects of parasitic infection on production