Crosslayer survivable mapping in Overlay-IP-WDM networks

Abstract

Abstract-Survivability is a critical requirement for reliable services in any network. As the Internet moves towards a three layer architecture consisting of Overlay on top of IP on top of WDM-based networks incorporating the interaction between and among network layers is crucial for efficient and effective implementation of survivability. This paper highlights the challenges of providing survivability in three-layer networks and develops a novel approach crosslayer survivable mapping to offer such survivability in an efficient way. We investigate the impacts of overlay network dependency on lower layer network layout in terms of the capacity allocated to overlay paths. The results demonstrate the impact due to layer dependency that it is more severe than initially anticipated making it clear that single layer network design is inadequate to assure service guarantees and efficient capacity allocation.

The Spine concept for improving network availability

“…For the network of Figure 1 with no protection, Table 2 lists the availabilities that a service provider can achieve by routing the unprotected flows on routes of different length. For the spine based network we group the s − d pairs into two groups based on whether they have a direct one hop WP route ON the spine {(1,2), (1,3), (1,4), (2,1), (3,1), (4,1)} or a one hop 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 WP route OFF the spine {(2,3), (2,4), (3,4), (3,2), (4,2),(4,3)}. Notice that in the case of the spine based network (i.e., bottom two rows) routes can contain links that are ON the spine, OFF the spine or a mix of ON and OFF the spine links.…”

Link availability mapping in infrastructure-based overlay networks

“…[20] gives the total number of segment-sets in a network graph as 2 | ( ( , ) ≥ 1 for all elements ( , ) of the matrix . Constraint (4) defines mapping with no backhaul as previously discussed in [11]. Similar to constraint (3), the symbol ⪯ in constraint (4) implies that ⪯ 1 means ( , ) ≤ 1 for all elements ( , ) of the matrix .…”

“…Each link is equivalent to two unidirectional links with an equal number of wavelengths and the same failure state, i.e., available or failed, in each link and with the same failure probability. Furthermore, let ( ) denote the incidence matrix, and let : ℒ ( ) → ℒ ( ) be a link mapping from network layer to network layer where each layer link is assigned to a subset of layer links [11]. The matrix is called the link mapping matrix.…”

“…One known problem is failure propagation -a situation in which a failure in a lower-layer network can result in one or more failures in an upper-layer network. Our previous work considered this problem in layered network in detail and developed crosslayer survivable mapping [11] technique, which considered link mapping between network layers, such that the upper-layer network is still survivable, i.e., connected, when any link in the lower-layer network fails. In this paper, we take a vertical look at the whole structure of the overlay-over-IP-over-WDM network as an instance of a three-layer network by considering the relationship between and among network graphs in different layers that also include link-level parameters such as availability, delay, among others.…”

Resilient network design: challenges and future directions

“…This model was extended in [30] to allow for traffic and survivability techniques at both layers and numerical results showed the advantages of providing survivability of two-layer traffic at the bottom layer when sharing spare capacity among all backup paths is allowed. In [29] sufficient conditions for elimination of backhaul in multi-layer network crosslayer survivable mapping were given and the model of [22] was extended to a three-layer context. In [32] we extended the cross-layer survivable mapping optimization problem to maximize the overlay network availability given the physical layer link and node availability information.…”