  Modern network applications demand low-latency traffic engineering in the
presence of network failure while preserving the quality of service constraints
like delay and capacity. Fast Re-Route (FRR) mechanisms are widely used for
traffic re-routing purposes in failure scenarios. Control plane FRR typically
computes the backup forwarding rules to detour the traffic in the data plane
when the failure occurs. This mechanism could be computed in the data plane
with the emergence of programmable data planes. In this paper, we propose a
system (called TEL) that contains two FRR mechanisms, namely, TEL-C and TEL-D.
The first one computes backup forwarding rules in the control plane, satisfying
max-min fair allocation. The second mechanism provides FRR in the data plane.
Both algorithms require minimal memory on programmable data planes and are
well-suited with modern line rate match-action forwarding architectures (e.g.,
PISA). We implement both mechanisms on P4 programmable software switches (e.g.,
BMv2 and Tofino) and measure their performance on various topologies. The
obtained results from a datacenter topology show that our FRR mechanism can
improve the flow completion time up to 4.6x$-$7.3x (i.e., small flows) and
3.1x$-$12x (i.e., large flows) compared to recirculation-based mechanisms, such
as F10, respectively.
