Bone gamma-carboxyglutamic acid-containing (Gla) protein (BGP, osteocalcin) is a noncollagenous protein of bone present in plasma and removed by the kidney. Plasma BGP has been shown to be elevated in patients with certain bone diseases. The present study evaluates serum BGP (S-BGP), serum alkaline phosphatase (S-AP), and urinary hydroxyproline excretion (U-OHP) in diseases with differing bone turnover rates, and compares the accuracy of these measurements for estimating bone mineralization (m) and resorption (r) rates. S-BGP, S-AP, U-OHP, and creatinine clearance (Clcr) were measured in patients with primary hyperparathyroidism (n = 13), hyperthyroidism (n = 6), and
BGP is considered a “Path Vector” routing protocol. BGP was not built to route within an Autonomous System (AS), but rather to route between AS’s. BGP maintains a separate routing table based on shortest AS Path and various other attributes, as opposed to IGP metrics like distance or cost.
Intuition suggests that an attacker can maximize the amount of traffic he attracts by widely announcing a short path that is not flagged as bogus by the secure protocol. Through simulations on an empirically-determined AS-level topol- ogy, we show that this strategy is surprisingly effective, even when the network uses an advanced security solution like S-BGP or data-plane verification. Worse yet, we show that these results underestimate the severity of attacks. We prove that finding the most damaging strategy is NP-hard, and show how counterintuitive strategies, like announcing longer paths, announcing to fewer neighbors, or triggering BGP loop-detection, can be used to attract even more traffic the strategy above. These counterintuitive examples are not merely hypotheti- cal; we searched the empirical AS topology to identify spe- cific ASes that can launch them. Finally, we find that a clever export policy can often attract almost as much traffic as a bo- gus path announcement. Thus, our work implies that mech- anisms that police export policies (e.g., defensive filtering) are crucial, even if S-BGP is fully deployed.
Several complete and systematic BGP security architectures are proposed  . S-BGP   suggests a modifica- tion of BGP which completely relies on the computationally intensive cryptographic operations to secure BGP. SPV  is in the same flavor but uses less resource consuming encryption system. On the contrary, the Inter-domain Route Validation (IRV)  neither revises BGP nor relies on cryptography, but constructs an overlay system outside of the BGP system to coordinate and authenticate the routing information among ASs. Secure Origin BGP (soBGP)  adopts a tradeoff between S-BGP and IRV. It proposes an extension of BGP and uses the existing BGP system to distribute and coordinate route validation information. At the same time, the decentralized ”Web-of-Trust” methodology is explored in ,  and . For example, the Pretty Secure BGP (psBGP)  utilizes the consistency checking among the distributed prefix- origin certifications to authenticate the prefixes’ origin-ASs. In , the consistency between the route advertisements to the same destination is exploited to ensure the integrity of the routing information. The above solutions can provide the protection against origin-AS and AS-Path hijacking. However, they cannot efficiently prevent redistribution hijacking. Al- though IRV provides the mechanism to protect redistribution hijacking, it costs excessive communication overhead since it needs to query the routing policy of every AS along the AS- Path hop by hop for every single route.
Secure Border Gateway Protocol (S-BGP) is the initial platform to secure BGP. Due to significant use of asymmetric cryptography and certificates, S-BGP becomes more expensive in storage, computation and time taken for key generation and verification. S-BGP also has higher cost for storing the detailed topology information . Pretty Secure BGP (psBGP) signifies a new alternative for prefix authentication through the decentralized authentication system. Every autonomous system keeps a new prefix assertion list (PAL), which include the address ownership declaration in the local autonomous systems and its neighbors. Prefix information is verified by checking regularity of prefix assertion list around its source .
The flexibility to set policies allowing any route to be preferred over any other has important ramifications, including unforeseen side-effects impacting other entities active in the routing system, widespread undetected misconfiguration and even conflicting con- figurations leading to bogus routing policies to activate. Given that ASes independently define their routing policies, it may happen that perplexing results of the interactions between ASes have been observed to cause important disruptions that affect the global routing system [1, 2]. The main reason behind this resides in the fact that the actual interdomain routing is the result of the interplay of many routing policies from ASes across the Internet, possibly bringing about a different outcome than the one expected. Consequently, in order to ensure the efficiency of their routing policies, ASes periodically control how their preferences resonate in the routing system or how others’ routing poli- cies are affecting them. To this end, most of the work related to our efforts described in Chapter 3 tackle the analysis of BGP raw data, which can be tricky and difficult. There are numerous efforts towards detecting security related routing conditions, such as prefix hijacking (e.g., PHAS ). Also, various tools exist to provide useful information for operators [17, 18]. Multiple operational misconfigurations have been reported , but attempts go far beyond this. They include RIPE Labs , which has a whole section devoted to tools that assists operators or Renesys  and BGPmon , which operate this type of services to operators for a fee.
Note: For each medication, the days supply must be >0. If the medication was started and then discontinued, CRS will recalculate the # Days Prescribed by subtracting the prescription date (i.e. visit date) from the V Medication Discontinued Date. Example: Rx Date=11/15/2010, Discontinued Date=11/19/2010, Recalculated # Days Prescribed=4. Medications must not have a comment of RETURNED TO STOCK. • BGP HEDIS ANTIANXIETY MEDS
Assessment using Passive Measurements: To validate our in- ferences we collaborate with major blackholing providers: IXPs in the USA, Central and South Europe. First, we validate the complete- ness of the visibility of our BGP datasets regarding the blackholed prefixes at each of the IXPs. We confirm that we have 99.5% visibility of all blackholing events that involve the IXPs route server. We also confirm that the large majority of blackholed prefixes are IPv4 /32s. Next, we check the impact on traffic. Therefore, we use IPFIX  traffic traces collected from the switching fabric of a major Euro- pean IXP, which offers a blackholing service. The traces, sampled at a rate of 1 out of 10K packets, provide flow-level information about the source/destination IP, port, and exchanged traffic volume via the IXP infrastructure on a per IXP member basis. To understand if and how much traffic is discarded, we focus on the blackholed prefixes with the largest traffic volumes at the IXP (these prefixes are blackholed throughout the week). Figure 9(c) shows the traffic volume in two stacked plots across one week. The values below the zero line are the traffic that is dropped at the IXP while the ones on top of the zero line show the traffic still traversing the IXP to its destination. We observe that a significant amount, i.e., more than 50% of traffic for some of the successfully announced /32s is dropped (negative part). Nevertheless, some traffic still is forwarded
BGP conditional route injection allows you to originate a prefix into a BGP routing table without the corresponding match. This feature allows more specific routes to be generated based on administrative policy or traffic engineering information in order to provide more specific control over the forwarding of packets to these more specific routes, which are injected into the BGP routing table only if the configured conditions are met. Enabling this feature will allow you to improve the accuracy of common route aggregation by conditionally injecting or replacing less specific prefixes with more specific prefixes. Only prefixes that are equal to or more specific than the original prefix may be injected. BGP conditional route injection is enabled with the bgp inject-map exist-mapcommand and uses two route maps (inject map and exist map) to install one (or more) more specific prefixes into a BGP routing table. The exist map specifies the prefixes that the BGP speaker will track. The inject map defines the prefixes that will be created and installed into the local BGP table.
Decision Tree based classification techniques are very effective in classification of anomalous BGP messages. A Random Forest classifier, on fine tuning, generates the best accuracy of 97.84% with a computation time of 15.692 seconds. A decision tree classifier, on fine tuning, generated the best accuracy of 97.38% with a computation time of 0.377 seconds. A GradientBoosting classifier, on fine tuning, generated the best accuracy of 95.41% with a computation time of 5.079 seconds. An AdaBoost classifier, on fine tuning, generated the best accuracy of 94.43% with a computation time of 11.883 seconds. Thus, Principal Component Analysis (PCA) proved to be very effective for dimensionality reduction, as it maximized variance for the newly created dimensions. This allowed the decision tree based classifiers to in turn maximize the entropy and information gain. Hence, it can be concluded that PCA followed by decision tree based classifiers such as Decision Trees, Random Forests, GradientBoosting and AdaBoost are useful for identification of anomalous BGP messages.
The last static route listed is used to point to the loopback address of our IBGP peer. This is necessary because we typically peer with loopback addresses for increased IBGP resilience. In our sample topology there is only one path to our IBGP peer, but in the real world there might be several paths to an internal peer. An IGP such as OSPF or IS-IS would usually be used to learn the best path to an internal peer. Peering with a loopback address allows the IGP path to change without affecting the BGP peering session assuming another route exists to the destination.
We use the Python Routeing Toolkit (PyRT) 1 to collect the I-BGP messages from the backbone. PyRT includes a BGP listener that establishes a peering session with a BGP-router and receives updates from it. The listener is passive because it does not send any updates to its peer. In this work, the PyRT listener was installed on a Linux PC in one of the backbone POPs to collect updates from a BGP route reflector (RR) in the backbone. Our listener appears as a route-reflector client to this particular router. Each up- date received is prepended with a header in MRTD 2 format (extended to include time-stamp of micro-second granu- larity) and then dumped to a file. The results reported in this paper is based on continuous data collected between November 2001 and April 2002. For the sake of compar- ison, we used separate instantiations of PyRT listener to also collect External BGP (E-BGP) updates from two other backbone routers in our network during the same period.
It might look surprising that R-BGP sometimes sends fewer updates than current BGP. This is due to the Root Cause Information (RCI) mechanism described in §6.2. In particular, when a link fails, current BGP may move to an alternate route that contains the same failed link and ad- vertise this new route to neighboring ASes. RCI provides an AS with enough information to locally purge all routes that traverse the failed link, thus preventing such useless updates and significantly reducing path exploration. One may wonder whether RCI significantly decreases the num- ber of messages and the failover advertisements eat most of this decrease, making the overall number of messages on par with BGP. This however is not the case. The num- ber of messages with just RCI is only a bit smaller, but we omit these results here to enhance readability.